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Objectives Prolidase plays a major role in collagen turnover, matrix remodeling, and cell growth. Benign prostatic hyperplasia (BPH) may be associated with an increased extracellular matrix deposition. Therefore, the present study was designed to investigate the plasma prolidase activity, oxidative status, and peripheral mononuclear leukocyte DNA damage in patients with BPH. Patients and methods Twenty-six male patients with BPH and 24 healthy male subjects were included in this study. Blood samples were collected from antecubital vein after an overnight fasting period, and the plasma was separated. Plasma prolidase activity, total antioxidant capacity (TAC), total oxidant status (TOS), and oxidative stress index (OSI) were determined. The peripheral lymphocyte oxidative DNA damage was determined using an alkaline single cell gel electrophoresis assay (comet assay). Results The plasma prolidase activity, TOS levels, OSI values, and peripheral mononuclear leukocyte DNA damage were significantly higher (P < 0.001), while the TAC levels were significantly lower (P < 0.001) in patients with BPH than controls. In BPH patients, the prolidase activity was significantly associated with TAC levels (r = −0.366, P < 0.05), TOS levels (r = 0.573, P < 0.001), and OSI (r = 0.618, P < 0.001) and peripheral mononuclear leukocyte DNA damage (r = 0.461, P < 0.001). Conclusions Our results showed that BPH might be associated with an increased oxidative stress, and also an increased plasma prolidase activity. Increased prolidase activity might play an important role in the etiopathogenesis and/or progression of BPH. [ABSTRACT FROM AUTHOR]

It has been shown that an increase in prolidase enzyme activity is correlated with increased rates of collagen turnover. In previous studies, it has been investigated that whether prolidase activity may be an index of liver fibrosis, but the results are controversial. Therefore, the aim of this study was to investigate serum prolidase activity in patients with biopsy-proven chronic viral hepatitis (CVH) and to find out whether prolidase enzyme activity is correlated with histopathological findings in those CVH patients. Fifty-four patients with CVH and 44 healthy controls were enrolled. Serum prolidase enzyme activity was measured spectrophotometrically. Serum prolidase activity was significantly higher in CVH than controls (p<0.001). A significant correlation was observed between serum prolidase activity and fibrosis score in patients with CVH (r=0.525, p<0.05). Our findings indicated that prolidase activity seems to be correlated with the level of fibrosis. Thus, serum prolidase activity may be an adjunctive tool in predicting the degree and stage of liver histopathological findings. [ABSTRACT FROM AUTHOR]

Introduction: Slow coronary flow (SCF) is described as the slow passage of contrast to distal coronaries despite anatomically normal coronary arteries. It has been shown that increased serum prolidase activity (SPA) correlates with collagen turnover. Increased collagen turnover might be associated with the development of atherosclerotic plaques. Aim: To investigate the relationship between serum prolidase activity and slow coronary flow. Material and methods: This cross-sectional study included 40 SCF patients (mean age: 55.0 ±9.5 years, 20 females) and 40 controls (mean age: 53.9 ±8.2 years, 21 females) with normal coronary anatomy and normal coronary flow. The Thrombolysis in Myocardial Infarction (TIMI) frame-count (TFC) method was used for SCF diagnosis. Serum prolidase activity was measured spectrophotometrically, and the relevant parameters were compared between the groups. Results: There were no statistically significant differences between the SCF and control groups in terms of basic demographic, clinical, and laboratory data. However, the SPA was significantly higher in the SCF group compared to the control (702.7 ±13.8 and 683.9 ±13.2 respectively, p < 0.001). Serum prolidase activity was significantly correlated with the mean TFC (r = 0.463, p < 0.001). The overall findings of this study support the predictive accuracy of the serum prolidase activity in our cohort, with a statistically significant ROC value of 681.3. Conclusions: Our study showed that SPA was increased in SCF patients. The activity of this enzyme was significantly correlated with the mean TFC. [ABSTRACT FROM AUTHOR]

The mechanism of a lower incidence of dermatological manifestations in patients treated with enalapril compared to patients treated with other ACE-inhibitors, e.g., captopril, is not known. The finding that prolidase plays an important role in collagen biosynthesis and that some angiotensin-converting enzyme inhibitors affect prolidase activity led us to evaluate its effect on collagen biosynthesis in cultured human skin fibroblasts. Since insulin-like growth factor (IGF-I) and transforming growth factor beta 1 (TGF-β1) are the most potent stimulators of both collagen biosynthesis and prolidase activity, and prolidase is regulated by β integrin signaling, the effect of enalapril and enalaprilat on IGF-IR, TGF-β1, and β integrin receptor expressions was evaluated. Cells were treated with milimolar concentrations (0.3 and 0.5 mM) of enalapril and enalaprilat for 24 h. The activity of prolidase was determined by colorimetic assay. Collagen biosynthesis was evaluated by radiometric assay. Expression of signaling proteins was evaluated using Western blot. It was found that enalapril- and enalaprilat-dependent increase in prolidase activity and expression was accompanied by parallel increase in collagen biosynthesis. The exposure of the cells to 0.5 mM enalapril and enalaprilat contributed to increase in IGF-IR and αβ integrin receptor as well as TGF-β1 and NF- κB p65 expressions. Enalapril- and enalaprilat-dependent increase of collagen biosynthesis in fibroblasts results from increase of prolidase activity and expression, which may undergo through activation of αβ integrin and IGF-IR signaling as well as upregulation of TGF-β1 and NF- κB p65, the inhibitor of collagen gene expression. [ABSTRACT FROM AUTHOR]

The oxythiamine (OXY) is antivitamin of thiamine. The finding that OXY increases the cytoplasmic concentration of pyruvate, known to enhance collagen biosynthesis, led us to investigate the mechanism of this antivitamin action on collagen biosynthesis in cultured human skin fibroblasts. Confluent fibroblasts were treated with micromolar concentrations (30-1,000 µM) of OXY for 24 and 48 h. It was found that OXY-dependent increase in collagen biosynthesis was accompanied by parallel increase in prolidase activity and level, compared to untreated cells. Since phosphoenolpyruvate (PEP) is known as an inhibitor of prolidase-the enzyme that plays important role in collagen biosynthesis, the mechanism of pyruvate interconversion was considered as a regulatory switch in collagen biosynthesis. In fact, 3-MPA, specific inhibitor of phosphoenolpyruvate carboxykinase (PEPCK), contributed to up-regulation of prolidase activity, suggesting that down-regulation of PEP formation is an underlying mechanism. Since collagen biosynthesis and prolidase activity are regulated by signal induced by activated αβ integrin receptor as well as insulin-like growth factor-I receptor (IGF-IR), the expression of these receptors was measured by Western immunoblot analysis. The exposure of the cells to OXY contributed to decrease in IGF-IR, αβ integrin receptor, pERK1/2, and NF- κB p65 expressions. It was accompanied by increase in total ERK1/2 expression and induction of phosphorylation of Akt protein. The data suggest that OXY-dependent increase of collagen biosynthesis in cultured human skin fibroblasts results from activation of prolidase activity and level, induction in pAkt expression and down-regulation of pERK1/2 and NF- κB p65, the known inhibitor of collagen gene expression. [ABSTRACT FROM AUTHOR]

Purpose: Although placental abruption is an acute condition, it is thought that the underlying pathology is chronic vasculopathy. Collagen is one of the important components of vascular structure, and there is a correlation between collagen turnover and prolidase enzyme activity (PEA). Thus, our aim was to assess whether there is a difference in serum oxidative stress level and PEA between pregnant women with placental abruption and those with a healthy pregnancy. Methods: The study group consisted of 36 pregnant women who underwent caesarean section with a diagnosis of placental abruption, while the control group comprised 36 pregnant women who underwent caesarean section due to obstetric reasons. Venous blood samples were drawn from all patients before caesarean section. In addition, tissue samples were obtained during caesarean section to evaluate tissue PEA. Results: No significant differences in demographic characteristics were detected between groups ( p > 0.05). Oxidative stress parameters, such as total oxidant status and oxidative stress index, were found to be significantly higher in the study group ( p < 0.001). Placental tissue PEA was found to be significantly higher in pregnant women with placental abruption (557.21 ± 135.41 vs. 426.68 ± 131.57 U/g, p < 0.001). In addition, a significant positive correlation was detected between PEA and oxidative stress parameters ( r = 0.332, p = 0.004). Conclusions: Our results indicated that elevated tissue PEA and serum oxidative stress levels are closely related to placental abruption. Thus, we think that increased collagen turnover may have a significant role in the aetiopathogenesis of placental abruption. [ABSTRACT FROM AUTHOR]

Introduction: Psoriasis is a chronic, inflammatory, T-cell-mediated and hyperproliferative skin disease characterized by erythematous, squamous, sharply circumscribed and infiltrated plaques. The metabolisms of the collagen proteins undergo considerable changes due to the acceleration of their turnovers as a result of increased prolidase activity in psoriasis patients. Aim: To determine the level of prolidase activity in psoriasis patients and evaluate its relationship with the oxidative system. Material and methods: The serum prolidase enzyme activity, total antioxidant levels and total oxidant levels of 40 psoriasis patients and a control group including 47 healthy individuals were analyzed by using their serum samples, and their oxidative stress indices were calculated. Results: The prolidase levels (p < 0.01), total oxidant levels (p < 0.01) and oxidative stress index levels (p < 0.001) of the patient group were higher than the corresponding parameters in the control group. The total antioxidant level was low (p < 0.01). Although a positive correlation was found between the prolidase and total antioxidant levels and the total oxidant level, no correlation was found between prolidase and the oxidative stress index. Conclusions: It has been determined that the activity of the prolidase enzyme increases due to the increased collage turnover in psoriasis patients. Increased serum oxidant levels and oxidative stress indices values may play a role in the pathogenesis of psoriasis. [ABSTRACT FROM AUTHOR]

Prolidase is the only enzyme capable of cleaving imidodipeptides containing C-terminal proline (Pro) or hydroxyproline and plays a crucial role in several physiological processes such as wound healing and cell proliferation. Here, we developed a new method to determine prolidase activity. This method is based on a novel fluorescence (FL) reaction selective for N-terminal glycine (Gly)-containing peptides using 3,4-dihydroxyphenylacetic acid (3,4-DHPAA). The 3,4-DHPAA can selectively react with Gly-Pro, the substrate for prolidase, and the prolidase activity is measured by monitoring the decrease in FL intensities. The prolidase activities in fibroblasts and HeLa cells were successfully measured by the proposed method. Compared with classical Chinard's method, our method does not require any caustic acids, pre-incubation to activate the enzyme, and heating for reaction with the detection reagent. The proposed method enables facile and specific measurement for biogenic prolidase activity.

The degradation of the main fibrillar collagens, collagens I and II, is a crucial process for skeletal development. The most abundant dipeptides generated from the catabolism of collagens contain proline and hydroxyproline. In humans, prolidase is the only enzyme able to hydrolyze dipeptides containing these amino acids at their C-terminal end, thus being a key player in collagen synthesis and turnover. Mutations in the prolidase gene cause prolidase deficiency (PD), a rare recessive disorder. Here we describe 12 PD patients, 9 of whom were molecularly characterized in this study. Following a retrospective analysis of all of them a skeletal phenotype associated with short stature, hypertelorism, nose abnormalities, microcephaly, osteopenia and genu valgum, independent of both the type of mutation and the presence of the mutant protein was identified. In order to understand the molecular basis of the bone phenotype associated with PD, we analyzed a recently identified mouse model for the disease, the dark-like ( dal ) mutant. The dal / dal mice showed a short snout, they were smaller than controls, their femurs were significantly shorter and pQCT and μCT analyses of long bones revealed compromised bone properties at the cortical and at the trabecular level in both male and female animals. The differences were more pronounce at 1 month being the most parameters normalized by 2 months of age. A delay in the formation of the second ossification center was evident at postnatal day 10. Our work reveals that reduced bone growth was due to impaired chondrocyte proliferation and increased apoptosis rate in the proliferative zone associated with reduced hyperthrophic zone height. These data suggest that lack of prolidase, a cytosolic enzyme involved in the final stage of protein catabolism, is required for normal skeletogenesis especially at early age when the requirement for collagen synthesis and degradation is the highest. [ABSTRACT FROM AUTHOR]

Methods 30 obese patients without metabolic syndrome (MetS), 34 non-diabetic obese patients with MetS, and 23 volunteer control subjects were enrolled in the study. Fasting plasma glucose (FPG), plasma glucose following 75 g glucose administration, high-density lipoproteincholesterol (HDL-C), high-density lipoprotein- cholesterol (LDL-C), total cholesterol, triglyceride (TG), total antioxidant status (TAS), total oxidative status (TOS), oxidative stress index (OSI), and prolidase activities of all subjects were analyzed. Results Prolidase levels was significantly higher in MetS group compared to both obese and control groups(p < 0.001 and p < 0.05 respectively). Prolidase was also higher in the obese group than in the control group (p < 0.05). Prolidase was negatively correlated with TAS and HDLC (r = -0,362, p < 0.001; r = -0.320, p < 0.01, respectively) and positively correlated with BMI, weight, waist-c, SBP, DBP, TG, TC, LDL-C. Conclusion Prolidase activity may have a role in the pathogenesis of metabolic syndrome. [ABSTRACT FROM AUTHOR]

Purpose: Most previous reports have shown that the basic mechanism of inguinal hernia involves insufficient collagen strength and metabolism. The aim of this study was to evaluate whether joint hypermobility is involved in the development of inguinal hernia in children and to investigate oxidative stress parameters and prolidase activity in tissue samples from children with inguinal hernia. Methods: This cross-sectional study involving 41 patients (age, 6.36 ± 2.96 years) with inguinal hernia treated in the pediatric surgery department of our institution and 40 age- and sex-matched controls (age, 6.02 ± 3.13 years) was performed from May to December 2011. Joint hypermobility was assessed using the Beighton criteria in all patients. Hernia sacs were analyzed with respect to the total antioxidative/oxidative status and prolidase activity. The patients were divided into two groups (inguinal hernia with and without hypermobility) according to a Beighton score cut-off of ≥6. Results: A total of 81 subjects aged 3-10 years participated. The ratio of joint hypermobility was significantly higher in patients than in controls ( p = 0.01). The prolidase activity, total oxidant status, and oxidative stress index were higher in tissue samples from patients with joint hypermobility ( p < 0.001). Conclusions: Our results show that joint hypermobility syndrome is associated with inguinal hernia in children and that increased prolidase activity and oxidative stress in tissue samples from patients with joint hypermobility syndrome are related to collagen tissue damage and turnover. [ABSTRACT FROM AUTHOR]

We aimed to elucidate the role of prolidase in NP pathogenesis by comparing serum and tissue prolidase activity (PA) in patients with and without NP. Patients with NP enrolled to the study group and widespread of NP evaluated using the scoring system of Lund-Mackay (LMS) according to the computer tomography records preoperatively. Patients without NP and who underwent inferior turbinate reduction operation were included to the control group in this study. All patients serum and tissue PA were analyzed. The levels of serum PA were significantly higher in the control group compared with the polyp group, whereas the levels of tissue PA were significantly higher in the polyp group than the controls. There was a significant negative correlation between serum PA and LMS. There was no significant correlation between tissue PA and serum PA, neither tissue PA and LMS in study group. We think that tissue and serum PA play an important role NP development. [ABSTRACT FROM AUTHOR]

Influenza A virus (IAV) entry is a multistep process that requires the interaction of the virus with numerous host factors. In this study, we demonstrate that prolidase (PEPD) is a cellular factor required by IAV for successful entry into target cells. PEPD was selected as a candidate during an entry screen performed on nonvalidated primary hits from previously published genome-wide small interfering RNA (siRNA) screens. siRNA-mediated depletion of PEPD resulted in the decreased growth of IAV during mono- and multicycle growth. This growth defect was independent of cell type or virus strain. Furthermore, IAV restriction was apparent as early as 3 h postinfection, and experiments in the absence of protein biosynthesis revealed that the nuclear import of viral ribonucleoprotein complexes (vRNPs) was already blocked in the absence of PEPD. These results led us to investigate which step during entry was affected. Receptor expression, IAV attachment, or IAV internalization was not dependent on the presence of PEPD. However, when looking at the distribution of incoming IAV particles in PEPD-knockdown cells, we found a localization pattern that differed from that in control cells: IAV mostly localized to the cell periphery, and consequently, viral particles displayed reduced colocalization with early and late endosome markers and fusion between viral and endosomal membranes was strongly reduced. Finally, experiments using a competitive inhibitor of PEPD catalytic activity suggested that the enzymatic function of the dipeptidase is required for its proviral effect on IAV entry. In sum, this study establishes PEPD as a novel entry factor required for early endosomal trafficking of IAV. [ABSTRACT FROM AUTHOR]

Prolidases, metalloproteases that catalyze the cleavage of Xaa-Pro dipeptides, are conserved enzymes found in prokaryotes and eukaryotes. In humans, prolidase is crucial for the recycling of collagen. To further characterize the essential elements of this enzyme, we utilized the Escherichia coli prolidase, PepQ, which shares striking similarity with eukaryotic prolidases. Through structural and bioinformatic insights, we have extended previous characterizations of the prolidase active site, uncovering a key component for substrate specificity. Here we report the structure of E. coli PepQ, solved at 2.0 Å resolution. The structure shows an antiparallel, dimeric protein, with each subunit containing N-terminal and C-terminal domains. The C-terminal domain is formed by the pita-bread fold typical for this family of metalloproteases, with two Mg(II) ions coordinated by five amino-acid ligands. Comparison of the E. coli PepQ structure and sequence with homologous structures and sequences from a diversity of organisms reveals distinctions between prolidases from Gram-positive eubacteria and archaea, and those from Gram-negative eubacteria, including the presence of loop regions in the E. coli protein that are conserved in eukaryotes. One such loop contains a completely conserved arginine near the catalytic site. This conserved arginine is predicted by docking simulations to interact with the C-terminus of the substrate dipeptide. Kinetic analysis using both a charge-neutralized substrate and a charge-reversed variant of PepQ support this conclusion, and allow for the designation of a new role for this key region of the enzyme active site. [ABSTRACT FROM AUTHOR]

Xaa-Pro dipeptidase (XPD; prolidase; EC 3.4.13.9) specifically hydrolyzes dipeptides with a prolyl residue at the carboxy-terminus. Xanthomonas spp. possess two different isoforms of XPD (48 and 43 kDa) which share ∼24% sequence identity. The XPD of 43 kDa in size (XPD43) from Xanthomonas spp. is unusual as it lacks the strictly conserved tyrosine residue (equivalent to Tyr387 in Escherichia coli aminopeptidase P) that is suggested to be important in the proton-shuttle transfer required for catalysis in the M24B (MEROPS) family. Here, the crystallization and preliminary X-ray analysis of XPD43 from X. campestris (GenBank accession No. NP_637763) are reported. Recombinant XPD43 was crystallized using the microbatch-under-oil technique. Diffraction data were collected on the recently commissioned protein crystallography beamline (PX-BL21) at the Indian synchrotron (Indus-2, 2.5 GeV) to 1.83 Å resolution with 100% completeness. The crystal belonged to space group P212121, with unit-cell parameters a = 84.32, b = 105.51, c = 111.35 Å. Two monomers are expected to be present in the asymmetric unit of the crystal, corresponding to a solvent content of 58%. Structural analysis of XPD43 will provide new insights into the role of the conserved residues in catalysis in the M24B family. [ABSTRACT FROM AUTHOR]

Decreased collagen biosynthesis and increased collagenolysis may induce aneurysmal progress in arterial walls. Prolidase plays a role in collagen synthesis. In this study, we sought to evaluate whether there is a correlation between nonatherosclerotic coronary artery aneurysms (CAAs) and prolidase activity. A total of 174 CAAs were diagnosed in 144 (2.1%) patients among 6845 coronary angiographies performed between 2009 and 2012. In all, 23 (15.9%) patients had nonatherosclerotic aneurysms. Prolidase activity was compared to the results of 19 healthy volunteers with normal coronary arteries. Demographic parameters were similar between the groups. Mean prolidase activity was 241.6 ± 54.4 mU/mL in the coronary aneurysm group and 730.3 ± 243.1 mU/mL in the control group (P < .001). The incidence of CAAs ranges between 0.3% and 5.3% in the general population. Decreased prolidase activity may reduce collagen biosynthesis that may contribute to aneurysm formation. [ABSTRACT FROM PUBLISHER]

Objective This study was performed to investigate serum prolidase enzyme activity and oxidative stress in patients diagnosed with fibromyalgia (FM). Methods The study population consisted of 40 patients with a previous diagnosis of FM and 30 healthy subjects. We measured serum prolidase enzyme activity, total antioxidant status (TAS), total oxidative status (TOS), oxidative stress index (OSI), and paraoxonase-1 (PON-1) levels. Results On average, FM patients were diagnosed within 3.2 years of symptom onset, and patients had a mean of 14 tender points. There were no significant differences between patients and controls in age, body mass index, serum TAS, or PON-1 levels. However, patients with FM demonstrated higher serum prolidase activity, TOS, and OSI than the control group. Serum prolidase activity was positively correlated with serum TOS, OSI, and visual analog scale pain and fatigue scores. No correlation was found between serum prolidase activity and FM duration or the average number of tender points. Discussion Our results demonstrate a previously unreported association between serum prolidase enzyme activity and FM. Increased prolidase activity may contribute to the pathogenesis of FM, and measuring serum prolidase enzyme activity may be a useful FM biomarker. [ABSTRACT FROM AUTHOR]

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Abstract: Here, an ultrasensitive electrochemiluminescence (ECL) aptasensor using in situ generated proline and polyamidoamine (PAMAM) dendrimers as coreactant for bis(2,2ʹ-bipyridyl)(5-amino-1,10-phenanthroline) ruthenium(II) (Ru) was successfully constructed for detection of thrombin (TB). Firstly, PAMAM combined with PtNPs was used as platform to assemble substantial Ru, prolidase (GPDA) and avidin labeled thrombin aptamer (avidin–TBA) to form PAMAM–PtNPs–Ru–GDPA–TBA bioconjugate. With the double aptamer-based sandwich assay, the bioconjugate was successfully modified on the electrode surface. The proposed aptasensor possessed three attractive advantages: PAMAM, as a tertiary amine substance, not only served as a platform to immobilize the PtNPs for further assembling prolidase (GPDA) and avidin–TBA, but also used as a coreactant of Ru to amplify the ECL signal. Furthermore, putting the coreactant and luminescence reagent together onto the electrode surface could effectively shorten the reaction time, improve the efficiency of electron transfer, and enhance the ECL signal. Lastly, the in situ generated coreactant proline for Ru catalyzed by GPDA could rapidly increase the concentration of proline around the electrode surface, which could also greatly amplify the ECL signal. With the several amplification factors mentioned above, the proposed ECL aptasensor showed a wide linear range from 0.01pmolL−1 to 10nmolL−1 with the detection limit of 5.0fmolL−1. The experimental results also indicated that the aptasensor exhibited excellent selectivity, stability and reproducibility. [Copyright &y& Elsevier]

Background: Moderate joint laxity is widespread in many joints of the body, and this condition is considered to be caused by an abnormality in the collagen structure. This study was carried out to determine the serum prolidase activity in female patients with benign joint hypermobility syndrome (BJHS), and to evaluate its correlation with their clinical features. Methods: A total of 45 patients with BJHS and 40 healthy controls were included in the study. All of the patients with BJHS met the Beighton diagnostic criteria. All the patients and the control group underwent a comprehensive examination of the locomotor system and took the New York Posture Rating Test. The examination and test results were recorded. Serum prolidase activity was measured in both the groups. Results: Prolidase activity was significantly lower in patients with BJHS (479.52 ± 126.50) compared to the healthy controls (555.97 ± 128.77) (p = 0.007). We found no correlation between serum prolidase activity and Beighton scores or New York rating test scores. On the other hand, mean prolidase activity was significantly lower in patients with pes planus or hyperlordosis compared to those without (p = 0.05, p = 0.03, respectively). We did not find such a correlation with the other clinical features. Conclusions: Significantly lower prolidase activity in patients with BJHS suggests that prolidase may affect the collagen metabolism and cause hyperlaxity. [ABSTRACT FROM AUTHOR]

Objectives To assess serum prolidase enzyme activity and oxidative stress in patients with Behçet's disease (BD). Methods The study population consisted of BD patients (n = 42) and healthy participants (n = 29). BD patients were classified as active (n = 18) or inactive (n = 24) according to disease activity. Serum prolidase enzyme activity, total antioxidant status (TAS), total oxidative status (TOS), oxidative stress index (OSI), and malondialdehyde (MDA) levels were measured. Results In BD patients with active disease, serum prolidase activity was significantly higher compared with the inactive and control participants. Serum prolidase activity was also significantly higher in all BD patients in comparison with controls. Serum prolidase activity was also positively correlated with OSI, C-reactive protein, and active BD. MDA, TOS, and OSI levels were all significantly higher in the BD group when compared with the healthy control participants. Serum TAS levels were significantly lower in BD patients in comparison with healthy controls. Conclusion High prolidase activity may indicate critical biological activities relevant to pathological events in BD, and this activity may be a biological indicator of disease. Further studies are needed to verify these findings. [ABSTRACT FROM AUTHOR]

Background Mycobacterium tuberculosis infection can activate the immune system, leading to characteristic pathological changes such as inflammatory granuloma, caseous necrosis, and cavity formation. Methods Clinical data of 187 cases of pulmonary tuberculosis (PTB) were analyzed using statistical methods, while serum levels of complement C4b (C4b), fibronectin (FN), and prolidase (PEPD) were detected using the ELISA method among the control, minimal PTB, moderate PTB, and advanced PTB groups. Results We found significantly higher levels of serum C4b and PEPD (P = 0.018, P = 0.003), and significantly lower levels of serum FN (P < 0.001) in PTB patients. Furthermore, the serum levels of 3 proteins were significantly different among 3 PTB groups. FN level was significantly higher in the moderate PTB group, compared with patients in the minimal and advanced PTB groups (P < 0.05, P < 0.01). PEPD level was significantly higher in the moderate PTB group, compared with the minimal PTB group (P < 0.05). Analysis of clinical data showed that serum albumin, C-reactive protein (CRP), prealbumin, and C4 were significantly higher (P < 0.05), while serum globulin was significantly lower in patients with PTB (P < 0.001). A significant negative correlation was found between C4b and albumin, prealbumin. On the other hand, a significant positive correlation was found between C4b and globulin, CRP, PEPD, as well as between PEPD and CRP (P < 0.05). Conclusions Our study showed that C4b, FN, and PEPD are associated with tissue damage, granuloma formation, and cavity formation, respectively, in patients with PTB. The present study provides a new experimental basis to understand the pathogenesis and pathological changes of PTB. [ABSTRACT FROM AUTHOR]

Association of oxidative stress and serum prolidase activity (SPA) has been reported in many chronic diseases. The study was aimed at evaluating the correlation of glucose and creatinine to SPA and oxidative stress in patients with diabetic nephropathy (DN) and end stage renal disease (ESRD) concerned with T2DM. 50 healthy volunteers, 50 patients with T2DM, 86 patients with DN, and 43 patients with ESRD were considered as control-1, control-2, case-1, and case-2, respectively. Blood glucose, creatinine, SPA, total oxidant status (TOS), total antioxidant status (TAS), and oxidative stress index (OSI) were measured by colorimetric tests. SPA, TOS, and OSI were significantly increased in case-1 and case-2 than control-1 and control-2, while TAS was significantly decreased (P < 0.001). Blood glucose was linearly correlated to SPA, TOS, TAS, and OSI in control-2, case-1 and case-2 (P < 0.001). Serum creatinine was linearly correlated with SPA, TOS, TAS and OSI in control-2 and case-1 (P < 0.001). In case-2, serum creatinine was significantly correlated with SPA only (P < 0.001). Thus, the study concluded that SPA and oxidative stress significantly correlated with blood glucose and creatinine. SPA, TOS, TAS, and OSI can be used as biomarkers for diagnosis of kidney damage. [ABSTRACT FROM AUTHOR]

Highlights: [•] UVC inhibits collagen biosynthesis through down-regulation of α 2 β 1 integrin signaling. [•] UVC-dependent inhibition of collagen biosynthesis is independent on prolidase activity. [•] UVC up-regulate NF-κB p65 expression in fibroblasts. [ABSTRACT FROM AUTHOR]

Purpose: Cellular processes are regulated by signals generated by adhesion receptors and growth factor receptors. IGFbinding protein 1 (IGFBP-1) is a molecule which may affect the both signaling pathways through inactivation of IGF-I (ligand for IGF-IR) and binding to RGD region of integrin receptors. Whether this phenomenon is important in communication between insulin-like growth factor receptor (IGF-IR) and β1-integrin receptor in regulation of prolidase activity and collagen biosynthesis is the aim of this study. Material and Method: We studied the effects of IGFBP-1, IGF-I, thrombin (integrin activator), echistatin (disintegrin), phosphatidylinositol 3-kinase inhibitor (LY-294002) and ERK 1/2 inhibitors (PD98059 and UO126) on prolidase activity, collagen biosynthesis and expression of proteins participating in pathways generated by these receptors. Results: Stimulation of β1-integrin and IGF-I receptors by standard ligands was proved to up-regulate collagen synthesis in cultured fibroblasts. IGFBP-1, similarly as echistatin and studied inhibitors, contributed to down-regulation of ERK1/2, Akt, mTOR expression and up-regulation of NFκB. It was accompanied by parallel decrease in prolidase activity and collagen biosynthesis. Conclusion: The data suggest that 'cross talk' between IGF-I receptor and integrin receptor may play important role in regulation of prolidase activity and collagen biosynthesis. [ABSTRACT FROM AUTHOR]

Aim: Prolidase deficiency is a rare autosomal recessive disease in which one of the last steps of collagen metabolism, cleavage of proline-containing dipeptides, is impaired. Only about 93 patients have been reported with about 10% also having systemic lupus erythematosus (SLE). Methods: We studied a large extended Amish pedigree with four prolidase deficiency patients and three heterozygous individuals for lupus-associated autoimmunity. Eight unaffected Amish children served as normal controls. Prolidase genetics and enzyme activity were confirmed. Antinuclear antibodies (ANA) were determined using indirect immunofluorescence and antibodies against extractable nuclear antigens were determined by various methods, including double immunodiffusion, immunoprecipitation and multiplex bead assay. Serum C1q levels were determined by enzyme-linked immunosorbent assay. Results: Two of the four homozygous prolidase deficiency subjects had a positive ANA. One had anti-doublestranded DNA, while another had precipitating anti-Ro. By the simultaneous microbead assay, three of the four had anti-Sm and anti-chromatin. One of the three heterozygous subjects had a positive ANA and immunoprecipitation of a 75 000 molecular weight protein. The unaffected controls had normal prolidase activity and were negative for autoantibodies. Conclusions: Prolidase deficiency may be associated with the loss of immune tolerance to lupus-associated autoantigens even without clinical SLE. [ABSTRACT FROM AUTHOR]

Glutamate excitotoxicity and oxidative stress are held responsible for the pathogenesis of Alzheimer’s disease (AD). Prolidase is known to have a crucial part in the recycling of proline for collagen synthesis. Elevated proline levels have been shown to increase glutamate concentration. To our knowledge, prolidase activity in AD has not yet been studied. In this study, we aimed to reveal the relationship of AD with oxidative stress and collagen turnover by comparing AD patients and healthy control group with regard to total antioxidant status (TAS), total oxidant status (TOS), and prolidase levels. Fifty patients (mean age, 72.5 ± 8.9 years) diagnosed with AD and a control group comprised of 39 healthy individuals (mean age, 69.1 ± 7.1 years) were compared relative to serum TAS, TOS, and prolidase levels. The relationship of cognitive performance with prolidase, TAS, and TOS was evaluated by Mini mental state examination (MMSE). Alzheimer’s disease group demonstrated statistically significantly higher prolidase and TOS levels as compared to the control group ( p = 0.01, p = 0.018, respectively). Total antioxidant status level was significantly lower in the dementia group than in the control group ( p = 0.032). MMSE manifested a negative correlation with prolidase and TOS levels ( p = 0.001, r = −0.33; p = 0.002, r = −0.32, respectively), while displaying a positive correlation with TAS levels ( p = 0.002, r = 0.32). In conclusion, elevated prolidase and TOS levels along with reduced TAS concentrations suggest that oxidative stress and collagen breakdown are involved in the cognitive impairment in AD. [ABSTRACT FROM AUTHOR]

The purpose of this study was to evaluate serum prolidase activity in patients with developmental dysplasia of the hip (DDH). Prolidase enzyme activity was measured spectrophotometrically to pointing out the collagen metabolism. The prolidase activity in patients with DDH was significantly higher than that in the control group ( p = 0.002). Furthermore, there was positive correlation between prolidase activity and dysplasia level. Increased serum prolidase activity may have played a role in the presence of DDH. We therefore hypothesized that the increased prolidase activity related to collagen turnover may be associated with etiopathogenesis and/or the progression of the disease. [ABSTRACT FROM AUTHOR]

This study aimed to evaluate serum prolidase activity and the effects of gender, body mass index (BMI), disease severity and duration, and therapy type on prolidase activity in patients with psoriatic as well as the relationship between serum NO · and prolidase levels in these patients. The study included 29 clinically documented plaque patients with psoriasis and 24 healthy volunteers. Data such as age, sex, BMI, duration and severity of disease, and type of therapy were assessed. NO · levels were determined by the Griess reaction. Serum prolidase assay is based on a colorimetric determination of proline by Chinard's reagent. We did not determine any difference in serum NO · levels of psoriatic patients when compared to controls. Serum prolidase levels in psoriasis patients were significantly higher than those in controls. There was no significant difference in prolidase activity between male and female. No statistically significant correlations were found between serum prolidase levels and BMI, PASI and disease duration. When compared between topical treatment group and systemic treatment group, there was no significant difference in serum prolidase activity. In conclusion, patients with psoriasis exhibit higher serum prolidase activity independent of gender, BMI, disease severity or duration, type of treatments or NO · level. However, further studies are needed to verify these findings as well as altered collagen synthesis in patients with psoriasis. [ABSTRACT FROM AUTHOR]

Aim Matrix metalloproteinases ( MMPs) have been considered to have a role in various pathological processes, including inflammatory response, cardiovascular disease and recently also in ovarian dysfunction. Since prolidase could be accepted as a matrix metalloproteinase, on the biochemical level, we aimed to evaluate serum prolidase activity and oxidative-antioxidative status in patients with polycystic ovary syndrome ( PCOS) and healthy individuals. Materials and methods Thirty-three PCOS patients and 28 healthy nonhyperandrogenic women were studied. Levels of prolidase activity, total antioxidant status ( TAS), total oxidant status ( TOS), oxidative stress index ( OSI), luteinizing hormone ( LH), follicle-stimulating hormone ( FSH), total testosterone (T) and prolactin ( PRL) were calculated. Results Levels of prolidase activities, total oxidant status, oxidative stress index, LH, PRL, and T were significantly higher in PCOS group than in the control group. Total antioxidant status levels were lower in PCOS group than healthy group, but it was not statistically significant . There was no significant difference between PCOS and control groups in term of FSH. Conclusion Women with PCOS have increased serum prolidase activity and oxidative stress. It might be hypothesized that elevated serum prolidase activity and oxidative stress may be associated with increased cardiovascular risk in PCOS and/or menstrual irregularities associated with this syndrome. [ABSTRACT FROM AUTHOR]

The role of estrogen in breast cancer progression and activation of prolidase activity and HIF-1α led us to study the effect of estrogen on nuclear HIF-1α expression in breast cancer estrogen-dependent MCF-7 and estrogen-independent MDA-MB-231 cells. We have found that in MCF-7 cells (expressing α and β estrogen receptor) cultured without estrogen receptor activator (phenol red, estradiol), HIF-1α was down-regulated, compared to the cells cultured with estrogen receptor activator. This effect was not observed in MDA-MB-231 cells (expressing only β estrogen receptor), suggesting that α estrogen receptor is involved in down-regulation of HIF-1α. However, in MDA-MB-231 cells (expressing high prolidase activity) cultured in the presence of prolidase substrates, Gly-Pro or Gly-HyPro, HIF-1α expression was induced in a dose-dependent manner, independently of estrogen receptor activation. In MCF-7 cells (with constitutively low prolidase activity) the effect of studied iminodipeptides on HIF-1α expression was much less pronounced but it was estrogen-dependent, showing importance of prolidase activity in mechanism of this process. The data were supported by confocal microscopy bio-imaging of HIF-1α in nucleus of MCF-7 and MDA-MB-231 cells that were cultured in the presence and absence of estrogen activator and prolidase substrates. It suggests that estrogen receptor may represent important therapeutic target in pharmacotherapy of estrogen receptor positive breast cancer, while ECM degradation enzymes, including prolidase may represent target in pharmacotherapy of estrogen receptor negative breast cancers. [ABSTRACT FROM AUTHOR]

Impaired wound healing is an important problem in diabetes mellitus; however, its pathogenesis remains unclear. We aimed to evaluate serum prolidase activity (SPA), an important marker of collagen turnover, in subjects with and without diabetic foot ulcers as compared with healthy controls. Twenty-seven patients with diabetic foot ulcers (foot ulcer group), 27 patients without diabetic foot ulcers (diabetic control group) and 27 healthy controls were enrolled. The study groups had similar age, sex distribution and body mass index. Metabolic and inflammatory parameters as well as SPA were determined. The diabetic foot ulcer group had significantly higher SPA (both p < 0.001) when compared with the diabetic and the healthy control groups. SPA showed a positive correlation with high-sensitive C-reactive protein and a negative correlation with high-density lipoprotein cholesterol levels ( r = 0.313, p = 0.021 and r = −0.233, p = 0.036, respectively). No correlation was detected between SPA and glycaemic parameters. SPA appears to be higher in patients with diabetic foot ulcers when compared with patients without diabetic foot ulcers and healthy controls. The underlying mechanisms of elevated SPA and its clinical significance in predicting the natural course of wound healing in diabetic foot ulcers needs to be further evaluation. [ABSTRACT FROM AUTHOR]

Background: Rheumatoid arthritis (RA) and chronic periodontitis (CP) are the most common chronic inflammatory diseases and have remarkable similar pathologies. The aim of this study is to investigate the impact of periodontal status on oxidative stress in patients with RA by evaluating serum oxidative parameters and prolidase levels. Methods: For this cross-sectional comparative study, the following four groups were composed of 20 individuals each (80 individuals total): 1) RA with CP (RA-CP group); 2) RA but periodontally healthy (RA-C group); 3) systemically healthy with CP (CP group); and 4) systemically and periodontally healthy (C group). Demographic, periodontal, rheumatological, and serum oxidative parameters as determined by serum total antioxidant status, total oxidant status, oxidative stress index (OSI), lipid hydroperoxide levels, paraoxonase, arylesterase, and ceruloplasmin activity, prolidase level, and total sulfhydryl groups were evaluated. Results: The OSI values of the RA-CP group were statistically significantly higher than those of the C group (P <0.05). The prolidase levels of the RA-C, RA-CP groups and the CP group were statistically higher than those of the C group (P = 0.001, P = 0.007, and P = 0.001, respectively). Conclusions: Although CP and RA each increase oxidative stress, in a small sample size these effects are only significant when both CP and RA are combined relative to neither exposure. In addition, increased prolidase levels in patients with RA and CP may be related to increased oxidative tissue damage. [ABSTRACT FROM AUTHOR]

Chronic otitis media usually presents with a benign tumor-like lesion of the temporal bone known as a cholesteatoma. The role of oxidative stress in the pathogenesis of chronic otitis media and cholesteatoma has not yet been fully explored. Therefore, the aim of this study was to investigate the oxidative stress markers and antioxidant enzymes in patients with cholesteatomatous and noncholesteatomatous chronic otitis media and in healthy subjects. A prospective controlled trial was performed on cholesteatomatous and noncholesteatomatous chronic otitis media patients in a tertiary referral center in a university hospital. A total of 75 subjects, including 25 cholesteatomatous and 25 noncholesteatomatous chronic otitis media patients and 25 healthy subjects participated in this study. Serum total oxidant status (TOS) and oxidative stress index (OSI) levels were significantly increased in the patient groups with or without cholesteatoma compared with the control group. Serum total antioxidant status (TAS) levels and Paraoxonase and arylesterase activity were significantly lower in the patient groups with or without cholesteatoma compared with the control group. Serum TOS and OSI levels were lower in the noncholesteatomatous group, whereas serum TAS levels were higher compared with the cholesteatomatous group. Serum arylesterase activity was significantly lower in the noncholesteatomatous group compared with the control group. The results of this study reveal that in cholesteatoma cases, the oxidative stress and antioxidant enzyme imbalance were more significant than in cases of chronic otitis media without cholesteatoma. [ABSTRACT FROM AUTHOR]

The finding that hydralazine (HYD) affects collagen metabolism led us to investigate the mechanism of its action on collagen biosynthesis, prolidase expression and activity, expression of αβ integrin, insulin-like growth factor-I receptor (IGF-IR), focal adhesion kinase (FAK), mitogen-activated protein (MAP) kinases (ERK, ERK), and transcription factors hypoxia-inducible factor-1α (HIF-1α) and nuclear factor-κB p65 (NF-κB p65) in human dermal fibroblasts. Confluent fibroblasts were treated with micromolar concentrations (50-500 μM) of HYD for 24 h. HYD had no influence on cell viability. It was found that HYD-dependent increase in collagen biosynthesis was accompanied by a parallel increase in prolidase activity and expression, HIF-1α expression, and decrease in DNA biosynthesis, compared to untreated cells. Since collagen biosynthesis and prolidase activity are regulated by a signal induced by activated αβ integrin receptor as well as IGF-IR, the expression of these receptors was measured by Western immunoblot analysis. The exposure of the cells to HYD contributed to the increase in IGF-IR expression without any effect on αβ integrin receptor and FAK expressions. It was accompanied by a decrease in expression of MAP kinases and NF-κB p65, the known inhibitor of collagen gene expression. The data suggest that the HYD-dependent increase of collagen biosynthesis in cultured human skin fibroblasts results from activation of IGF-IR expression and prolidase activity and downregulation of NF-κB p65. [ABSTRACT FROM AUTHOR]

Human liver prolidase, a metal-dependent dipeptidase, is being tested as a potential catalytic bioscavenger against organophosphorus (OP) chemical warfare nerve agents. The purpose of this study was to determine whether persistent and high-levels of biologically active and intact recombinant human (rHu) prolidase could be introduced in vivo in mice using adenovirus (Ad). Here, we report that a single intravenous injection of Ad containing the prolidase gene with a 6× histidine-tag (Ad-prolidase) introduced high-levels of rHu prolidase in the circulation of mice which peaked on days 5–7 at 159±129U/mL. This level of prolidase is ∼120 times greater than that of the enzyme level in mice injected with Ad-null virus. To determine if all of Ad-prolidase-produced rHu prolidase was exported into the circulation, enzyme activity was measured in a variety of tissues. Liver contained the highest levels of rHu prolidase on day 7 (5647±454U/g) compared to blood or any other tissue. Recombinant Hu prolidase hydrolyzed DFP, a simulant of OP nerve agents, in vitro. In vivo, prolidase overexpression extended the survival of 4 out of 6 mice by 4–8h against exposure to two 1× LD50 doses of DFP. In contrast, overexpression of mouse butyrylcholinesterase (BChE), a proven stoichiometric bioscavenger of OP compounds, protected 5 out of 6 mice from DFP lethality and surviving mice showed no symptoms of DFP toxicity. In conclusion, the results suggest that gene delivery using Ad is capable of introducing persistent and high levels of human liver prolidase in vivo. The gene-delivered prolidase hydrolyzed DFP in vitro but provided only modest protection in vivo in mice, delaying the death of the animals by only 4–8h. [ABSTRACT FROM AUTHOR]

Abstract: Prolidase deficiency (PD) is a rare inborn disorder of collagen metabolism characterized by chronic recurrent cutaneous ulceration. We report a novel 3bp insertion in the 12th exon of the PEPD gene in two Kashmiri siblings with prolidase deficiency phenotype. This mutation results in addition of an extra alanine residue at the amino-acid position number 304 of prolidase peptide. The structural analysis showed that this Ala insertion is located at the helix (a.a. 300–320), which contains several important hydrogen bonds between residues essential for structural folding for the enzyme activity. In silico analysis suggests that this insertion mutation might distort or bend the helical feature to affect the hydrogen-bond network between residues of neighboring secondary structures and deform the metal-binding geometry of the enzyme. Although approximately 70 PEPD gene mutations and polymorphisms have been reported in various ethnic groups, we however report, for the first time, the identification of insertion mutation in human the PEPD gene. [Copyright &y& Elsevier]

Objectives. To investigate peripheral, seminal and varicose venous wall prolidase enzyme activities and their relationships between sperm parameters in patients with varicocele. Design and methods. Prolidase enzyme activities were determined in blood, seminal fluid and varicose vein walls in patients with grade 3 varicocele. Sperm parameters were also measured and the relationships between prolidase enzyme and sperm parameters were assessed by statistical correlation analysis. Results. There was a significant and negative correlation between sperm counts and varicose venous wall prolidase enzyme activities (r = −0.618, p < 0.001) and a positive significant correlation between sperm counts and seminal fluid prolidase enzyme activities (r = 0.676, p < 0.001). None of the parameters were correlated with sperm motility indices. Conclusion. Varicose venous wall prolidase enzyme activity could be an important factor in progression of azoospermia and infertility in patients with varicocele. [ABSTRACT FROM AUTHOR]

Prolidase is the only human enzyme responsible for the digestion of iminodipeptides containing proline or hydroxyproline at their C-terminal end, being a key player in extracellular matrix remodeling. Prolidase deficiency (PD) is an intractable loss of function disease, characterized by mutations in the prolidase gene. The exact causes of activity impairment in mutant prolidase are still unknown. We generated three recombinant prolidase forms, hRecProl-231delY, hRecProl-E412K and hRecProl-G448R, reproducing three mutations identified in homozygous PD patients. The enzymes showed very low catalytic efficiency, thermal instability and changes in protein conformation. No variation of Mn(II) cofactor affinity was detected for hRecProl-E412K; a compromised ability to bind the cofactor was found in hRecProl-231delY and Mn(II) was totally absent in hRecProl-G448R. Furthermore, local structure perturbations for all three mutants were predicted by in silico analysis. Our biochemical investigation of the three causative alleles identified in perturbed folding/instability, and in consequent partial prolidase degradation, the main reasons for enzyme inactivity. Based on the above considerations we were able to rescue part of the prolidase activity in patients’ fibroblasts through the induction of Heath Shock Proteins expression, hinting at new promising avenues for PD treatment. [ABSTRACT FROM AUTHOR]

Abstract: Human prolidase is a binuclear metalloenzyme, which can potentially function as a catalytic bioscavenger for organophosphorus (OP) nerve agents. Although the biochemical properties of native prolidase purified from human erythrocytes, liver, kidney, and fibroblast cells are well known, it is very poorly characterized with regard to its OP hydrolyzing activity. Also, the high cost of purification of large quantities of native enzyme limits its use as a bioscavenger. Thus, recombinant human prolidase with similar biochemical properties to those of native enzyme would be more suitable as a catalytic bioscavenger. In this study, we established an Escherichia coli expression system, which produced a large amount of tagged human liver prolidase that was purified to over 95% purity from the soluble fraction of cell lysate by affinity chromatography on Streptavidin-agarose resin. The catalytic properties of the recombinant enzyme were compared in vitro with those of highly purified prolidase I isolated from human erythrocytes. The catalytic properties of recombinant prolidase overlap with those of the erythrocyte-derived native enzyme. Both enzymes efficiently hydrolyzed diisopropylfluorophosphate, sarin, soman, tabun and cyclosarin, but were much less efficient at hydrolyzing paraoxon and methyl paraoxon. These results suggest that human prolidase expressed in E. coli is suitable for further development as a catalytic bioscavenger for OP nerve agents. [Copyright &y& Elsevier]

Prolidase, also known as Xaa-Pro dipeptidase or peptidase D (PEPD), is a ubiquitously expressed cytosolic enzyme that hydrolyzes dipeptides with proline or hydroxyproline at the carboxyl terminus. In this article, however, we demonstrate that PEPD directly binds to and activates epidermal growth factor receptor (EGFR), leading to stimulation of signaling proteins downstream of EGFR, and that such activity is neither cell-specific nor dependent on the enzymatic activity of PEPD. In line with the pro-survival and pro-proliferation activities of EGFR, PEPD stimulates DNA synthesis. We further show that PEPD activates EGFR only when it is present in the extracellular space, but that PEPD is released from injured cells and tissues and that such release appears to result in EGFR activation. PEPD differs from all known EGFR ligands in that it does not possess an epidermal growth factor (EGF) motif and is not synthesized as a transmembrane precursor, but PEPD binding to EGFR can be blocked by EGF. In conclusion, PEPD is a ligand of EGFR and presents a novel mechanism of EGFR activation. [ABSTRACT FROM AUTHOR]

Abstract: Human prolidase, the enzyme responsible for the hydrolysis of the Xaa-Pro/Hyp peptide bonds, is a key player in the recycling of imino acids during the final stage of protein catabolism and extracellular matrix remodeling. Its metal active site composition corresponding to the maximal catalytic activity is still unknown, although prolidase function is of increasing interest due to the link with carcinogenesis and mutations in prolidase gene cause a severe connective tissue disorder. Here, using EPR and ICP-MS on human recombinant prolidase produced in Escherichia coli (hRecProl), the Mn(II) ion organized in a dinuclear Mn(II)–Mn(II) center was identified as the protein cofactor. Furthermore, thermal denaturation, CD/fluorescence spectroscopy and limited proteolysis revealed that the Mn(II) is required for the proper protein folding and that a protein conformational modification is needed in the transition from apo- to Mn(II)loaded-enzyme. The collected data provided a better knowledge of the human holo-prolidase and, although limited to the recombinant enzyme, the exact identity and organization of the metal cofactor as well as the conformational change required for activity were proven. [Copyright &y& Elsevier]

Aim: We aimed to determine the relationship both paraoxonase and prolidase activitys in the patients with malignant glioma. Methods: In this study, serum paraoxonase and prolidase activitys were measured on 25 healthy human and 25 patients with malignant glioma. Paraoxonase activity was measured using diethyl-p-nitrophenylphosphate as substrate, as previously described. The prolidase activity was used for measurement of proline by the method proposed by Myara et al., which is a modification of Chinard's method (Myara et al.,1982). Results: The paraoxonase and prolidase activitys were significantly lower in serum of patients with malignant glioma as a whole compared to controls. Conclusions: In the current study, the activity paraoxonase and prolidase decreased in the patients with malignant glioma. As a result the paraoxonase and prolidase decreased seems to play a major role in the pathophysiology of malignant glioma. This is the first report on serum paraoxonase and prolidase decreased activities in patients with malignant gliomas. [ABSTRACT FROM AUTHOR]

Dopamine receptor agonists and L-dihydroxyphenylalanine ( L-DOPA) counteract dopamine loss in the striatum and are therefore used in the treatment of Parkinson's disease (PD). T-Lymphocytes express some features of the dopaminergic system, and their function or activation might be regulated by dopaminergic treatments. Two-dimensional electrophoresis of total protein extract from T-lymphocytes was performed to identify therapy-induced proteome changes in T-cells of 17 patients with PD. Specific protein level alterations were further validated by Western blotting. Of 17 enrolled patients, 11 were treated with different doses of L-DOPA; in this group, we found that the levels of two spots, corresponding to ATP synthase subunit β and proteasome subunit β type-2, correlated linearly with the L-DOPA daily dose. Moreover, we identified seven proteins (prolidase, actin-related protein 2, F-actin-capping protein subunit β, tropomyosin α-3 chain, proteasome activator complex subunit 1, peroxiredoxin 6, and a glyceraldehyde-3-phosphate dehydrogenase isoform) whose levels were significantly different in patients treated with dopamine agonists. These findings demonstrate that dopaminergic stimulation has important effects on T-cell proteome in patients under long-term treatment. Therefore, therapies acting on the dopaminergic system may have additional effects on the immune system. © 2012 IUBMB, IUBMB Life, 64(10):846-852, 2012 [ABSTRACT FROM AUTHOR]