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An unprecedented and direct PS‐MS (paper spray ionization mass spectrometry) method was proposed for the detection of native peptides, that is, glutathiones (GSHs), homoglutathiones (hGSHs), and phytochelatins (PCs), in basil (Ocimum basilicum L.) roots before and after cadmium exposure. The roots were submitted to cold maceration followed by sonication with formic acid as the extractor solvent for sample preparation. PS‐MS was used to analyze such extracts in the positive mode, and the results allowed for the detection of several GSHs, hGSHs, and PCs. Some of these PCs were not distinguished in the control samples, that is, basil roots not exposed to cadmium. Other PCs were noticed in both types of roots, uncontaminated and cadmium‐contaminated, but the intensities were higher in the former samples. Moreover, long‐time exposure to cadmium stimulated the formation of some of these PCs and their cadmium complexes. The results, therefore, provided some crucial insights into the defense mechanism of plants against an external stress condition due to exposure to a toxic heavy metal. The present study represents a promising alternative to investigate other crucial physiological processes in plants submitted to assorted stress conditions. [ABSTRACT FROM AUTHOR]

We developed a simple, paper‐based device that enables sensitive detection by mass spectrometry (MS) without solid phase extraction or other sample preparation. Using glass fiber filter papers within a 3D printed holder, the device employs electrokinetic manipulations to stack, separate, and desalt charged molecules on paper prior to spray into the MS. Due to counter‐balanced electroosmotic flow and electrophoresis, charged analytes stack on the paper and desalting occurs in minutes. One end of the paper strip was cut into a sharp point and positioned near the inlet of a MS. The stacked analyte bands move toward the paper tip with the EOF where they are ionized by paper spray. The device was applied to analysis of PFAS in tap water with sub part‐per‐trillion detection limits in less than ten minutes with no sample pretreatment. Analysis of opioids in urine also occurs in minutes. The crucial parameters to enable stacking, separation, and MS ionization of both positively and negatively charged analytes were determined and optimized. Experimental and computational modeling studies confirm the electrokinetic stacking and analyte transport mechanisms. On‐paper separations were carried out by stacking analyte bands at different locations depending on their electrophoretic mobility, achieving baseline separation in some cases. [ABSTRACT FROM AUTHOR]

We developed a simple, paper‐based device that enables sensitive detection by mass spectrometry (MS) without solid phase extraction or other sample preparation. Using glass fiber filter papers within a 3D printed holder, the device employs electrokinetic manipulations to stack, separate, and desalt charged molecules on paper prior to spray into the MS. Due to counter‐balanced electroosmotic flow and electrophoresis, charged analytes stack on the paper and desalting occurs in minutes. One end of the paper strip was cut into a sharp point and positioned near the inlet of a MS. The stacked analyte bands move toward the paper tip with the EOF where they are ionized by paper spray. The device was applied to analysis of PFAS in tap water with sub part‐per‐trillion detection limits in less than ten minutes with no sample pretreatment. Analysis of opioids in urine also occurs in minutes. The crucial parameters to enable stacking, separation, and MS ionization of both positively and negatively charged analytes were determined and optimized. Experimental and computational modeling studies confirm the electrokinetic stacking and analyte transport mechanisms. On‐paper separations were carried out by stacking analyte bands at different locations depending on their electrophoretic mobility, achieving baseline separation in some cases. [ABSTRACT FROM AUTHOR]

A commentary of the paper 'Humanin variant P3S is associated with longevity in APOE4 carriers and resists APOE4‐induced brain pathology' that appeared recently in Aging Cell. The possible association of a mitochondrial haplogroup with a disease is frequently discussed. The Humanin peptide encoded by the mtDNA has been shown to play an important regulatory role in cell metabolism. There are variants of Humanin caused by different mutations and it is known that the potent form of Humanin, termed S14G, is found naturally in the people of haplogroup U6a7a1a because they have the mutation m.A2672G; however it has not been shown that having this mutation is indeed beneficial. In their paper, the authors suggest that the mitochondrial DNA mutation, m.C2639T, may be beneficial in people who are in haplogroup N1b and also carry APOE4. The mutation changes the common form of Humanin to Humanin P3S. In the study, the researchers looked at a group of Ashkenazi women who were over the age of 95, and found that a higher proportion of them carried APOE4, suggesting that Humanin P3S protected them against the adverse effects of APOE4. A study in a mouse model supported this finding by showing treatment with Humanin P3S reduced APOE4‐induced brain pathology. In the world population, there are about 500,000 Ashkenazi in haplogroup N1b, predominantly in the subgroup N1b1b1; and there are about 9.5 million non‐Ashkenazi people with the mutation m.C2639T and are therefore also in haplogroup N1b and have Humanin P3S. However, the researchers have yet to show Humanin P3S is of benefit in non‐Ashkenazi people. This paper raises the possibility of a therapeutic use of Humanin P3S in the treatment of Alzheimer's disease. [ABSTRACT FROM AUTHOR]

A single amino acid in a peptide sequence can play an important role to tune the self‐assembly and hydrogelation behaviour. Here, a C‐terminal cysteine‐containing ultrashort peptide hydrogelator forms hydrogel through non‐covalent and covalent interactions. Interestingly, the hydrogel is insoluble in water and buffer solutions at different pH values (1‐13) and is thixotropic and injectable. In recent years, removing dyes from contaminated water has become a significant concern because of the shortage of freshwater resources. Therefore, the adsorption of dyes through a reliable, straightforward, nontoxic, cheap, and environmentally friendly adsorbent has become a popular topic. Hence, the hydrogelator was exploited to remove organic dyes from wastewater, harnessing its applicability in the gel phase and solid supports (filter paper and cotton). [ABSTRACT FROM AUTHOR]

Phage display biopanning is used to identify peptides that show material-selective adsorption, effectively distinguishing between the cellulose of paper and the printed toner of standard office laser printers. These genetically selected 12mer peptides can selectively coat either non-printed cellulose or printed toner patterns. Furthermore, triazolindione ligation chemistry is exploited to introduce, for example, dyes or functional peptides selectively to the coatings. The strategy offers an easy access towards the patterned functionalization of paper-based materials, which potentially is of relevance for low-cost diagnostics or biomedical devices. [ABSTRACT FROM AUTHOR]

Cation‐π interactions, often found in protein assemblies, are characterized by favorable electrostatic interactions between an aromatic π‐electron surface and a positively charged species. There are evidences that reveal the importance of cation‐π interactions between arginine and aromatic residues in protein structure and function. In this paper, the effect of cation‐π interactions on the aggregation propensity of peptides derived from human islet polypeptide (hIAPP) was explored using UV resonance Raman and fluorescence spectroscopy. By employing an analog of hIAPP22–29 in which Phe‐23 is replaced with tryptophan (NWGAILSS), we were able to demonstrate an increase in the amyloidogenic propensity of this mutant in the presence of Zn2+ that is attributable to cation‐π interactions. In contrast, no cation‐π interactions were observed when the cationic F23R analog of hIAPP22–29 (NRGAILSS) was allowed to interact with NWGAILSS. From these observations, it was surmised that in these peptides, the dominant interaction between arginine and tryptophan involves the π‐cloud of the guanidino group and the indole ring, not cation‐π interactions. The spectroscopic data, supported by density functional theory‐based simulation results, suggest that arginine‐tryptophan interaction involves π‐π stacking where the guanidino group is oriented parallel to the indole ring. These hydrophobic interactions, coupled with the hydrotropic effect of the guanidine functionality of arginine, led to a delay in the aggregation kinetics of NWGAILSS. These unique interactions were further exploited to design a peptide inhibitor of full‐length amylin self‐assembly. [ABSTRACT FROM AUTHOR]

A simple method is described for the patterned deposition of Teflon on paper to create an integrated platform for parallel organic synthesis and cell-based assays. Solvent-repelling barriers made of Teflon-impregnated paper confine organic solvents to specific zones of the patterned array and allow for 96 parallel flow-through syntheses on paper. The confinement and flow-through mixing significantly improves the peptide yield and simplifies the automation of this synthesis. The synthesis of 100 peptides ranging from 7 to 14 amino acids in length gave over 60 % purity for the majority of the peptides (>95 % yield per coupling/deprotection cycle). The resulting peptide arrays were used in cell-based screening to identify 14 potent bioactive peptides that support the adhesion or proliferation of breast cancer cells in a 3D environment. In the future, this technology could be used for the screening of more complex phenotypic responses, such as cell migration or differentiation. [ABSTRACT FROM AUTHOR]

A simple method is described for the patterned deposition of Teflon on paper to create an integrated platform for parallel organic synthesis and cell-based assays. Solvent-repelling barriers made of Teflon-impregnated paper confine organic solvents to specific zones of the patterned array and allow for 96 parallel flow-through syntheses on paper. The confinement and flow-through mixing significantly improves the peptide yield and simplifies the automation of this synthesis. The synthesis of 100 peptides ranging from 7 to 14 amino acids in length gave over 60 % purity for the majority of the peptides (>95 % yield per coupling/deprotection cycle). The resulting peptide arrays were used in cell-based screening to identify 14 potent bioactive peptides that support the adhesion or proliferation of breast cancer cells in a 3D environment. In the future, this technology could be used for the screening of more complex phenotypic responses, such as cell migration or differentiation. [ABSTRACT FROM AUTHOR]

A relaxin‐like gonad‐stimulating peptide (RGP), Aso‐RGP, featuring six cysteine residues, was identified in the Crown‐of‐Thorns Starfish (COTS, Acanthaster cf. solaris) and initially produced through recombinant yeast expression. This method yielded a single‐chain peptide with an uncleaved C‐peptide (His Tag) and suboptimal purity. Our objective was to chemically synthesize Aso‐RGP in its mature form, comprising two chains (A and B) and three disulfide bridges, omitting the C‐peptide. Furthermore, we aimed to synthesize a newly identified relaxin‐like peptide, Aso‐RLP2, from COTS, which had not been previously synthesized. This paper reports the first total chemical synthesis of Aso‐RGP and Aso‐RLP2. Aso‐RGP synthesis proceeded without major issues, whereas the A‐chain of Aso‐RLP2, in its reduced and unfolded state with two free thiols, presented considerable challenges. These were initially marked by "messy" RP‐HPLC profiles, typically indicative of synthesis failure. Surprisingly, oxidizing the A‐chain significantly improved the RP‐HPLC profile, revealing the main issue was not synthesis failure but the peptide's aggregation tendency, which initially obscured analysis. This discovery highlights the critical need to account for aggregation in peptide synthesis and analysis. Ultimately, our efforts led to the successful synthesis of both peptides with purities exceeding 95 %. [ABSTRACT FROM AUTHOR]

INTRODUCTION: One of the main allergens in soybeans is glycinin, which seriously impacts the normal lives of allergic people. Previous studies have confirmed that thermal processing and thermal processing combined with ultrahigh‐pressure processing could significantly reduce the antigenicity of glycinin. The dominant antigen region of acidic peptide chain A2 of G2 subunit was located by phage display experiment. METHODS: In this paper, overlapping peptides and alanine substitution techniques were used to explore the key amino acids that significantly affect the antigenicity of A2 peptide chain. The purity of peptide 1, peptide 2 and peptide 3 was identified by mass spectrometry and high‐performance liquid chromatography, and the results showed that the purity of the synthesized overlapping peptide was more than 90%. SDS‐PAGE showed that the peptide was successfully coupled with bovine serum albumin. The antigenicity of the coupling peptide was tested by ELISA and Dot‐Blot, and the allergenicity was detected by reacting with the serum of patients with soybean globulin allergy. CONCLUSION: The results showed that peptide 3 has stronger antigenicity and sensitization. Alanine substitution technology allowed one to perform site‐directed mutagenesis on peptide 3. Dot‐Blot and ELISA tests showed that D259, E260, E261, Q263 and C266 may be the key amino acids that significantly affect the antigenicity of peptide 3. The research presented is of great significance for correctly guiding the production of safe food and preventing the occurrence of food allergic diseases. © 2023 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Six peptide toxins (Magi 1–6) were isolated from the Hexathelidae spider Macrothele gigas. The amino acid sequences of Magi 1, 2, 5 and 6 have low similarities to the amino acid sequences of known spider toxins. The primary structure of Magi 3 is similar to the structure of the palmitoylated peptide named PlTx-II from the North American spider Plectreurys tristis (Plectreuridae). Moreover, the amino acid sequence of Magi 4, which was revealed by cloning of its cDNA, displays similarities to the Na+ channel modifier δ-atracotoxin from the Australian spider Atrax robustus (Hexathelidae). Competitive binding assays using several 125I-labelled peptide toxins clearly demonstrated the specific binding affinity of Magi 1–5 to site 3 of the insect sodium channel and also that of Magi 5 to site 4 of the rat sodium channel. Only Magi 6 did not compete with the scorpion toxin LqhαIT in binding to site 3 despite high toxicity on lepidoptera larvae of 3.1 nmol/g. The Kis of other toxins were between 50 pM for Magi 4 and 1747 nM for Magi 1. In addition, only Magi 5 binds to both site 3 in insects (Ki=267 nM) and site 4 in rat brain synaptosomes (Ki=1.2 nM), whereas it showed no affinities for either mammal binding site 3 or insect binding site 4. Magi 5 is the first spider toxin with binding affinity to site 4 of a mammalian sodium channel. [Copyright &y& Elsevier]

The article discusses the use of diagnostic biomarkers for prediction of adverse early pregnancy outcomes. Topics mentioned include the use of a biomarker for reduction of clinical burden of pregnancy of unknown location cases, the controversies surrounding the use of biomarkers, such as human chorionic gonadotrophin and progesterone, and the categorization of biomarkers in early pregnancy based on their biological origin.

1. A new diagonal etectrophoretic technique for determining the order of the lysine-containing tryptic peptides of a protein is described. The protein is converted into its trifluoracetyl derivative, digested enzymatically (or chemically), and the resulting peptides separated by paper electrophoresis. The paper is then treated with ammonia vapour, which re-exposes the ε-amino groups of the lysine residues, and submitted to a second electrophoresis at right angles to the first direction. Peptides containing lysine residues, together with the N-terminal peptide of the protein, are found to lie off a diagonal formed by all other peptides, whence they may be readily purified. A study of these peptides enables the order of the lysine-containing tryptic peptides in the protein to be deduced. 2. The technique has been successfully tested with insulin. 3. When the method was applied to porcine pepsin, the four tryptic peptides isolated were easily ordered and the carboxyl-terminal sequence of the protein shown to be Arg-Gln-Tyr-TyrThr-Val-Phe-Asp-Arg-Ala-Asn-Asn-Lys-Val-Gly-Leu-Ala-Pro-Val-Ala. The thee basic ammo acid residues in the molecule are thus found clustering towards the C-terminus of the polypeptide chain. 4. A common ancestral gene for porcine pepsin and bovine (calf) rennin is suggested by the close homology between the C-terminal sequents of the two proteins. [ABSTRACT FROM AUTHOR]

Synthetic therapeutic peptides are a complex and popular class of pharmaceuticals. In recent years, peptides with proven therapeutic activity have gained significant interest in the market. The determination of synthetic peptide enantiomeric purity plays a critical role in the evaluation of the quality of the medicine. Since racemization is one of the most common side reactions occurring in AAs or peptides, enantiomeric impurities such as D‐isomers can form during the peptide synthesis or can be introduced from the starting materials (e.g., AAs). The therapeutic effect of a synthetic or semi‐synthetic bioactive peptide molecule depends on its AA enantiomeric purity and secondary/tertiary structure. Therefore, the enantiomeric purity determination for synthetic peptides is supportive for interpreting unwanted therapeutic effects and determining the quality of synthetic peptide therapeutics. However, enantiomeric purity analysis encounters formidable analytical challenges during chromatographic separation, as D/L isomers have identical physical–chemical properties except stereochemical configuration. To ensure peptides AA stereochemical configuration whether in the free or bound state, sensitive and reproducible quantitative analytical method is mandatory. In this regard, numerous analytical techniques were emerged for the quantification of D‐isomeric impurities in synthetic peptides, but still, very few reports are available in the literature. Thus, the purpose of this paper is to provide an overview of the importance, regulatory requirements, and various analytical methods used for peptide enantiomeric purity determination. In addition, we discussed the available literature in terms of enantiomeric impurity detection, common hydrolysis procedural aspects, and different analytical strategies used for sample preparation. [ABSTRACT FROM AUTHOR]

Biohybrid catalysts that operate in aqueous media are intriguing for systems chemistry. In this paper, we investigate whether control over the self‐assembly of biohybrid catalysts can tune their properties. As a model, we use the catalytic activity of functional hybrid molecules consisting of a catalytic H‐dPro‐Pro‐Glu tripeptide, derivatized with fatty acid and nucleobase moieties. This combination of simple biological components merged the catalytic properties of the peptide with the self‐assembly of the lipid, and the structural ordering of the nucleobases. The biomolecule hybrids self‐assemble in aqueous media into fibrillar assemblies and catalyze the reaction between butanal and nitrostyrene. The interactions between the nucleobases enhanced the order of the supramolecular structures and affected their catalytic activity and stereoselectivity. The results point to the significant control and ordering that nucleobases can provide in the self‐assembly of biologically inspired supramolecular catalysts. [ABSTRACT FROM AUTHOR]

Mass spectrometry is widely employed in various analytical fields for both compound identification and quantification. While in the case of compound identification, the high‐resolution instrument has increased selectivity and characterization efficiency; in the case of quantitative analysis, some critical tasks actually remain. In particular, different compounds exhibit different ionization efficiency, and this introduces the need to have a calibration standard for each analyte. In this paper, we present a new elaborative data technology, which makes it possible to standardize calibration between different instruments and molecules, making it absolute. The method was applied to data acquired by means of liquid chromatography mass spectrometry by means of an ion trap analyzer. The approach is based on the correlation of the ion trap space charge effect and the analyte concentration. The method was validated in the analysis of compounds having different polarity: hydrossitirosol, arginine, thyodiglicolic acid, and a peptide mixture of bacteria cultures derived the human gut microbiome where was found poliovirus. Moreover, it was used to obtain the absolute quantitation of peptides originating from the tryptic digestion of bacterial proteins in the fecal samples. It was therefore possible to identify and quantify different derived bacterial proteins of the poliomyelitis virus coded in bacteria derived from the gastrointestinal tract. [ABSTRACT FROM AUTHOR]

Multiple myeloma (MM) is a neoplastic proliferation of plasma cells and remains an incurable disease because of the development of drug resistance. Histone deacytylase (HDAC) inhibitors are a new class of chemotherapeutic reagents that cause growth arrest and apoptosis of neoplastic cells. Depsipeptide, a new member of the HDAC inhibitors, was found to be safe in humans and has been shown to induce apoptosis in various cancers. In order to evaluate the effects of depsipeptide, a MM cell line, U266 [interleukin (IL)-6 dependent], was analysed for viability and apoptosis. The combined effect of depsipeptide with melphalan and changes in BCL-2 family proteins (BCL-2, BCL-XL, BAX and MCL-1) were also investigated. In addition, the RPMI 8226 cell line (IL-6 independent), and primary patient myeloma cells were also analysed for apoptosis after depsipeptide treatment. Depsipeptide induced apoptosis in both U266 and RPMI 8226 cell lines in a time- and dose-dependent fashion, and in primary patient myeloma cells. We also demonstrated that depsipeptide had an additive effect with melphalan (10 μmol/l). BCL-2, BCL-XL and MCL-1 showed decreased expression in depsipeptide-treated samples. Based on recent clinical trials demonstrating minimal clinical toxicity, our study supports the future clinical utilization of depsipeptide in the management of MM. [ABSTRACT FROM AUTHOR]

Chromogranin B (CgB) is a member of the granin family of neuroendocrine secretory proteins, which has been proposed to play a role in secretory granule biogenesis and as a precursor to bioactive peptides. The cloning of CgB in a phylogenetically distant vertebrate, the frog Rana ridibunda, reveals a modest overall homology (35–40%) with mammalian CgB. However, the sequences of the N- and C-terminal regions are more highly conserved (57–65% amino acid identity) and may give rise to novel regulatory peptides. In frog, intense expression of CgB mRNA was observed in particular structures of the brain and in the distal lobe of the pituitary. [Copyright &y& Elsevier]

Medium sized molecules such as peptides and macrocycles have recently drawn much attention as potent sources of medicinal lead compounds, whereas the possibility of obtaining a practical drug from them remains limited. The present paper describes a concept of discovering novel medicinal targets or binding modes as well as lead compounds by the one‐peptide‐on‐one‐bead (OPOB) technology for comprehensive screening. The difficulty and problems in conventional drug discovery methods that generally deal with one predetermined target are considered. The building blocks used for the present libraries were selected based on previous results in development of peptidic drugs. Each constituent has the common structure of cyclic form prepared by disulfide of cysteinyl residues or thioether linkages, additionally a methionine residue was inserted for the site‐specific rapid cleavage by cyanogen bromide to liberate the immobilized peptides allowing reliable characterization by MALDI‐TOF‐MS/MS without LC‐purification. Thus, a high throughput construction method for cyclic peptide libraries as well as characterization of single bead are proposed for drug discovery. [ABSTRACT FROM AUTHOR]

The development of peptidomimetics to modulate the conformational profile of peptides has been extensively studied in the fields of biological and medicinal chemistry. However, large‐scale synthesis of peptidomimetics with both an ordered sequence and a controlled secondary structure is highly challenging. In this paper, the framework of peptidomimetics has been designed to be alternating an achiral α,α‐disubstituted α‐amino acid unit and a chiral α‐methylphenylalanine unit. The polymers are synthesized via invented Ugi reaction‐based polycondensation technique. The chiral higher‐order structures of the alternating peptides are evaluated mainly through circular dichroism (CD) spectroscopy. The UV–Vis and CD spectra of the polymers in three solvents are systematically measured at various temperatures. The anisotropic factors of CD (gCD) values are calculated to know the chiroptical response. The results indicate the characteristic conformational behaviors. In a polar solvent, the hydrogen bonds between the N‐H group of MePhe unit and the C=O of α,α‐diphenylglycine unit outweigh the intraresidue hydrogen bonds in α,α‐diphenylglycine unit, leading to the formation of a prevailing preferred‐handed 310‐helical conformation. On the other hand, in a less polar solvent, the intrachain hydrogen bonds switch to intraresidue hydrogen bonds in α,α‐diphenylglycine unit, which make the polymer adopting a prevailing extended planar C5‐conformation. [ABSTRACT FROM AUTHOR]

Keywords: bariatric surgery; mass spectrometry; peptide YY EN bariatric surgery mass spectrometry peptide YY 763 765 3 05/05/23 20230601 NES 230601 We note that Maurer et al., in their correspondence,[1] have raised some concerns about the preanalytical and analytical validation of the peptide YY (PYY) assay described in our paper 'The postprandial secretion of peptide YY SB 1 sb SB -36 sb and SB 3 sb SB -36 sb in obesity is differentially increased after gastric bypass versus sleeve gastrectomy'.[2] The validation and assay characteristics were not the primary objectives of the paper. We have studied the stability of both PYY species with our inhibitor mix containing DPP4 inhibitor and Aprotinin, where we spiked PYY SB 1 sb SB -36 sb and PYY SB 3 sb SB -36 sb into plasma EDTA and LH from three different volunteers. [Extracted from the article]

Tissue damage caused by an infection or an autoimmune disease triggers degradation of collagen in the extracellular matrix (ECM), which further enhances inflammation. Therefore, improving ECM in an inflamed tissue can be exploited as a potential therapeutic target. A recent study emphasised an innovative approach against COVID‐19 using polymerised type I collagen (PTIC) that improves disease severity through a hitherto unknown mechanism. In this paper, we provide an overview of potential mechanism that may explain the anti‐inflammatory effect of collagen peptides. In addition,the paper includes a brief summary of possible side effect of collagen deposition in inflammatory diseases. Altogether, current knowledge suggests that collagen may potentially reduce the residual risk in inflammatory diseases; however, the detailed mechanism remains elusive. [ABSTRACT FROM AUTHOR]

Summary: Nisin is a peptide with antibacterial activity against a variety of pathogens. It was originally obtained from a Lactococcus lactis. It is classified as a class I bacteriocin, as it is synthesised by ribosomes and post‐translationally modified. It has been studied extensively and has a wide range of applications in the food industry, biomedicine, veterinary, and research fields. It is approved as a food preservative by the Food and Agriculture Organization (FAO). What's more, nisin, the only antimicrobial peptide that has generally considered as safe (GRAS) status from both World Health Organization (WHO) and Food and Drug Administration (FDA), has the potential to become an important natural antibiotic as bacteria become more resistant to traditional antibiotics. However, nisin purified from biological sources usually results in low yields and high production costs, limiting industrial‐scale manufacturing and application in other fields. Hence, more methods need to be used to optimise the production of nisin. Therefore, this paper aimed to understand the structure and biosynthesis mechanism of nisin and to summarise the innovative methods for increasing the production of nisin using biosynthesis regulation. [ABSTRACT FROM AUTHOR]

Rationale: The observed isotope distribution is an important attribute for the identification of peptides and proteins in mass spectrometry-based proteomics. Sulphur atoms have a very distinctive elemental isotope definition, and therefore, the presence of sulphur atoms has a substantial effect on the isotope distribution of biomolecules. Hence, knowledge of the number of sulphur atoms can improve the identification of peptides and proteins. Methods: In this paper, we conducted a theoretical investigation on the isotope properties of sulphur-containing peptides. We proposed a gradient boosting approach to predict the number of sulphur atoms based on the aggregated isotope distribution. We compared prediction accuracy and assessed the predictive power of the features using the mass and isotope abundance information from the first three, five and eight aggregated isotope peaks. Results: Mass features alone are not sufficient to accurately predict the number of sulphur atoms. However, we reach near-perfect prediction when we include isotope abundance features. The abundance ratios of the eighth and the seventh, the fifth and the fourth, and the third and the second aggregated isotope peaks are the most important abundance features. The mass difference between the eighth, the fifth or the third aggregated isotope peaks and the monoisotopic peak are the most predictive mass features. Conclusions: Based on the validation analysis it can be concluded that the prediction of the number of sulphur atoms based on the isotope profile fails, because the isotope ratios are not measured accurately. These results indicate that it is valuable for future instrument developments to focus more on improving spectral accuracy to measure peak intensities of higher-order isotope peaks more accurately. [ABSTRACT FROM AUTHOR]

Background: There are no diagnostic and/or prognostic markers of the treatment outcome in patients receiving allergen immunotherapy (AIT). Although numerous allergen epitopes are known, their value in this context has not been investigated. This paper deals with re‐evaluation of sera from patients who underwent AIT against rBet v 1 for treatment of their soya allergy (BASALIT trial). Objective: To evaluate the diagnostic and/or prognostic potential of allergen epitopes recognition by antibodies from patients with birch‐related soya allergy before and after rBet v 1‐immunotherapy. Methods: PR‐10 epitope‐binding profiles from 34 patients were identified in silico using a statistical peptide phage display at start and at end of AIT. IgE‐ and IgG‐binding to these peptide epitopes was measured in peptide microarrays. Clinical relevance of epitopes was evaluated by comparing these measurements to a number of treatment outcome measures recorded during double‐blind placebo‐controlled food challenge at start and end of AIT. Results: We showed that IgG‐ and IgE‐recognition of peptide epitopes after AIT were surrogate markers of 5 out of 12 analysed treatment outcome measures using this patient cohort. Seven epitopes were identified from multiple PR‐10 allergen sequences. Twenty‐six peptide epitopes were used for IgG and IgE measurements. IgE‐binding to one of the epitopes was associated with stronger intensity of oral tingling/itching after ingesting soya at start of AIT. IgG recognizing two other epitopes at start of AIT could predict decreased Cor a 1‐specific IgE concentration (p =.043) and decreased lip swelling intensity (p =.016) after AIT. Tolerance to increasing amounts of soy at food challenge correlated with IgG‐binding to another epitope at start of AIT (p =.046). Conclusion: IgG‐ and IgE‐binding to peptide epitopes in PR‐10 is a potential indicator of the outcome and clinical course of AIT of soya‐sensitized patients with rBet v 1. [ABSTRACT FROM AUTHOR]

Experimental observations have shown that peptides are chemically modified under plasma treatment, which impacts the function and lifetime of a protein. This paper investigates the interactions of reactive oxygen species (ROS) produced in atmospheric plasmas and peptides. Results show that the reactions typically start with the H abstraction from the side chain of amino acids. As the reactions continue, the introduction of O atoms is the most common reaction, and the formation of double C = C bonds, detachment of carboxyl groups, and cleavage of the ring are also observed. Moreover, the degree of oxidative modification of the peptides increases with increasing doses of ROS. This study reveals the formation and breaking of chemical bonds and the generation of new reactive groups in the structure of peptides under plasma treatment, which enables us to understand the mechanisms of plasma medicine deeply. [ABSTRACT FROM AUTHOR]

This document is a corrigendum for an article titled "Assembly of Glycopeptides in Living Cells Resembling Viral Infection for Cargo Delivery." The corrigendum acknowledges an inadvertent mistake in the stereocenters of the galactose units in the peptides or the modified serine, which has been corrected. The correction does not affect the results and conclusions of the paper. The corrigendum includes revised figures and apologizes for any inconvenience caused. [Extracted from the article]

Peptide Science publishes peer‐reviewed papers covering all aspects of peptide synthesis, materials, structure and bioactivity. The journal includes both experimental and theoretical studies and serves the interdisciplinary biochemical, biomaterials, biophysical and biomedical research communities. [ABSTRACT FROM AUTHOR]

Immunogenic cell death (ICD) arises when cells are under stress, and their membranes are damaged. They release damage‐associated molecular patterns (DAMPs) that stimulate and drive the type and magnitude of the immune response. In the presence of an antigen, DAMPs ride the longevity and efficacy of antigen‐specific immunity. Yet, no tool can induce the controlled ICD with predictable results. A peptide‐based tool, [II], is designed that aggregates in the cell and causes cell membrane damage, generates ICD and DAMPs release on various cell types, and hence can act as an adjuvant. An influenza vaccine is prepared by combining [II] with influenza hemagglutinin (HA) subunit antigens. The results show that [II] induced significantly higher HA‐specific immunoglobulin G1 (IgG1) and IgG2a antibodies than HA‐only immunized mice, while the peptide itself did not elicit antibodies. This paper demonstrates the first peptide‐aggregation induced immunogenic rupture (PAIIR) approach as a vaccine adjuvant. PAIIR is a promising adjuvant with a high potential to promote universal protection upon influenza HA vaccination. [ABSTRACT FROM AUTHOR]

CD247, which is also known as CD3ζ, CD3H, CD3Q, CD3Z, IMD25, T3Z and TCRZ, encodes CD3ζ protein, which is expressed primarily in natural killer (NK) and T cells. Since the discovery of the ζ peptide in 1986, it has been continuously investigated. In this paper, we review the composition, molecular mechanisms and regulatory factors of CD247 expression in T cells; and review the autoimmune diseases, tumours and inflammatory diseases associated with CD247, providing a detailed and comprehensive reference for further research on the mechanism of CD247 and related diseases. [ABSTRACT FROM AUTHOR]

Since the global peptide drug market demand has been predicted to increase, highly efficient and inexpensive mass scale peptides are required. However, the production process raises questions about the cost of energy input, scale‐up production, raw materials, and solvents treatment. This paper introduces 2 methods for the 2–4 mer oligopeptides bond formation for batch reaction utilizing 50–100 mol% of a mild Brønsted acid under the mild condition. One of the methods has been capably adapted to flow synthesis at room temperature using organic solvents with boiling points below 100 °C. The method applies the tert‐butoxycarbonyl amino methoxy group, forming the desired dipeptide without solvent at mild temperatures. Furthermore, the conversion of the carboxylic acid leaving the group to phenyl ester promotes peptide bond formation, and the reaction were applied to di, tri, and tetrapeptide bond formation in excellent yield without notable racemization at ambient temperature (up to >99 % yield and 99 : 1 dr). Finally, this study proposes this new production method to overcome the limited scale‐up production by reaction device scale: liquid phase biomimetic catalytic peptide flow synthesis utilizing a mild Brønsted acid. [ABSTRACT FROM AUTHOR]

Electrically controllable deoxyribonuclic acid (DNA) nanolevers are used to investigate the binding interaction between Influenza A/Aichi/2/1968 and the peptide called "PeB", which specifically binds the viral surface protein hemagglutinin. PeB is immobilized on gold electrodes of a "switchSENSE" biochip by conjugation to DNA‐strands that are hybridized to complementary anchors. The surface‐tethered DNA strand carries a fluorophore while the complementary strand is a multivalent arrangement carrying up to three PeB peptides. The nanolevers are kept upright (static) by applying a negative potential. Signal read‐out for this static measurement mode is the change in fluorescence intensity due to changes in the local environment of the dye upon binding. Measurements of virus‐peptide interaction show that the virus material specifically binds to the immobilized peptides and remains bound throughout the measurement time. Immobilized viruses are subsequently used as ligands to characterize oligovalent peptide binding to hemagglutinin, revealing rate constants of the interaction. Moreover, three Influenza A subtypes are compared in their binding behavior. Overall, this paper shows the ability to immobilize virus material on a sensor surface, which allows to target virus‐proteins in their native environment. The "switchSENSE" method is therefore applicable to characterize virus‐receptor interactions. [ABSTRACT FROM AUTHOR]

Glucagon‐like peptide‐1 receptor agonists (GLP‐1 RAs) have become agents of choice for people with type 2 diabetes (T2D) with established cardiovascular disease or in high‐risk individuals. With currently available GLP‐1 RAs, 51%‐79% of subjects achieve an HbA1c target of less than 7.0% and 4%‐27% lose 10% of body weight, illustrating the need for more potent agents. Three databases (PubMed, Cochrane, Web of Science) were searched using the MESH terms 'glucagon‐like peptide‐1 receptor agonist', 'glucagon receptor agonist', 'glucose‐dependent insulinotropic peptide', 'dual or co‐agonist', and 'tirzepatide'. Quality of papers was scored using PRISMA guidelines. Risk of bias was evaluated using the Cochrane assessment tool. An HbA1c target of less than 7.0% was attained by up to 80% with high‐dose GLP‐1 RAs and up to 97% with tirzepatide, with even up to 62% of people with T2D reaching an HbA1c of less than 5.7%. A body weight loss of 10% or greater was obtained by up to 50% and up to 69% with high‐dose GLP‐1 RAs or tirzepatide, respectively. The glucose‐ and weight‐lowering effects of the GLP‐1/glucagon RA cotadutide equal those of liraglutide 1.8 mg. Gastrointestinal side effects of high‐dose GLP‐1 RAs and co‐agonists occurred in 30%‐70% of patients, mostly arising within the first 2 weeks of the first dose, being mild or moderate in severity, and transient. The development of high‐dose GLP‐1 RAs and the dual GLP‐1/glucose‐dependent insulinotropic peptide RA tirzepatide resulted in increasing numbers of people reaching HbA1c and body weight targets, with up to 62% attaining normoglycaemia with 15‐mg tirzepatide. Whether this will also translate to better cardiovascular outcomes and affect treatment guidelines remains to be studied. [ABSTRACT FROM AUTHOR]

The interactions between ligands and polymers are of great interest to drug delivery researches. In this work for the first time, Poly (lactic‐co‐glycolic acid) based polymers with arginine‐glycine‐aspartate (RGD) peptide ligands which are immediately self‐assembled into micellar nanoparticles (NPs) in contact with water have been investigated in the atomistic level. In this regard, the effect of polymer and RGD concentrations on the stability, size, interaction energies and other molecular properties of nanocarriers has been investigated using molecular dynamics simulation. In the next step, the microfluidic micellization and docetaxel (DTX) encapsulation has been simulated in comparison to bulk micellization. Results indicated that by employing only 20 wt % RGD‐conjugated polymer, the particles reach the stable properties and compactness without DTX. But, when the DTX was added, 30 wt.% of RGD‐conjugated polymers that assembled in microfluidic system is the best state nanocarrier for the smart target drug delivery for transfer of DTX drug into the Cancer cell. Comparisons of the results acquired in the current paper confirmed that engineering and tuning the self‐assembly in the interface of phases in microchennel resulted in a precise control on the particle size and resulted in the preparation of smaller and more stable NPs that can be exploited as ultra‐small, smart drug carriers. [ABSTRACT FROM AUTHOR]

Presents a lists of forthcoming papers for the journal "European Journal of Biochemistry." "Substance-p-related and Neurokinin-a-related Peptides From the Brain of the cod and Trout," by Jensen and J. M. Conlon; "Biochemical and Photochemical Properties of the Photophobic Receptors From Halobacterium Halobium and Natronobacterium Pharaonis," by B. Scharf, B. Pevec, and B. Hess; "Phosphatidylinositol-glycan-specific Phospholipase D is an Amphiphilic Glycoprotein That in Serum is Associated With High-Density Lipoproteins," by M. C. Hoener and U. Brodbeck.

Lists forthcoming papers on biochemistry, compiled as of April 1992. 'The Effect of Polylysine on Casein-kinase-2 Activity is Influenced by Both the Structure of the Protein/Peptide Substrates and the Subunit Composition of the Enzyme,' by F. Meggio, B. Boldyreff and O. Marin; 'Increased Steady-State Levels of Several Mitochondrial and Nuclear Gene Transcripts in Rat Hepatoma With a Low Content of Mitochondria,' by K. Luctakova and S. Kuzela; 'Phycobilisome Structure in the Cyanobacteria Mastiglocladus laminosus and Anabaena Sp. PCC 7120,' by M. Glauser and D.A. Bryant.

This article presents titles of forthcoming research papers related to biochemistry. Some of the titles include "Solubilization and Partial Characterization of a Multienzyme Complex of DNA Synthesis From Human Lymphoblastoid Cells"; "Nucleotide Sequence of Cloned cDNA Coding for Mouse Casein"; "Effects of Acetylation on the Binding of N-Terminal Peptides of Histone H4 to DNA."

Peptide Science publishes peer‐reviewed papers covering all aspects of peptide synthesis, materials, structure and bioactivity. The journal includes both experimental and theoretical studies and serves the interdisciplinary biochemical, biomaterials, biophysical and biomedical research communities. [ABSTRACT FROM AUTHOR]

Cardiovascular diseases (CVD) are a significant and growing burden on global health services, and it is now accepted that impairment of vascular function represents a major preliminary step in the development of CVD. There is considerable interest in identifying both causal factors of impaired vascular function, as well as related nutritional factors that may lower the risk of developing CVD, and food‐derived bioactive peptides and amino acids have emerged as one such area. Dairy foods contain two groups of proteins, whey proteins and caseins, which represent a rich source of bioactive peptides that are released during food processing and/or digestion. These peptides have a number of physiological activities including the potential to reduce blood pressure. Research, including acute and longer‐term randomised controlled trials, animal models and in vitro models has demonstrated the potential impact of dairy proteins on vascular function. The purpose of this paper is to narratively review the evidence, primarily from randomised controlled trials, examining the effects of whey proteins, their peptides and amino acids on vascular function and related issues including blood pressure. In addition, it will explore the potential underlying mechanisms responsible for these effects. It concludes that there is increasing evidence that whey proteins, and notably the bioactive peptides and amino acids released during their digestion, can have beneficial effects on aspects of vascular function and thus contribute to CVD risk reduction. It also highlights a number of beneficial effects of whey proteins including those on blood pressure, arterial stiffness, nitric oxide production and inflammation. [ABSTRACT FROM AUTHOR]

Introduction: The MHC‐peptide interaction has a subtle influence on host resistance to virus. This paper aims to study the relationship between MHC‐peptide interaction and MHC‐related virus‐resistance. Methods: By 3D homology modeling, the structure of chicken BF2 molecule BF2*0201 (PDB code: 4d0d) was studied and compared with the known structures of BF2 molecule BF2*0401 (PDB code: 4e0r) to elucidate the characteristics of BF2*0201‐binding antigenic peptides. Results: The results show that due to the amino acid difference between the two binding groove of 4e0r and 4d0d, the size of the binding groove of the two are 1130 ų and1380 ų respectively, indicating the amino acid species that 4e0r binding peptide has lower selectivity than 4d0d; and because of large side chain conformation of Arg (especially Arg111) of 4e0r replaced by small side chain Tyr111 of 4d0d, the volume of central part of the binding groove of 4d0d is obviously larger than that of 4e0r, indicating that the restrictive of binding antigenic peptides for 4d0d is narrower than that of 4e0r; and on account of the chargeability of the binding groove of the two are different, namely the binding groove chargeability of 4e0r (strong positive polarity) and 4d0d (weak negative polarity). Conclusion: There are generally more peptides presented by the BF2 of B2 haplotype than by that of B4 haplotype, leading to more resistance of B2 than that of B4 to virus. [ABSTRACT FROM AUTHOR]

This paper describes a method that combines a microfluidic device and self‐assembled monolayers for matrix‐assisted laser desorption/ionization mass spectrometry (SAMDI) mass spectrometry to calculate the cooperativity in binding of calcium ions to peptidylarginine deiminase type 2 (PAD2). This example uses only 120 μL of enzyme solution and three fluidic inputs. This microfluidic device incorporates a self‐assembled monolayer that is functionalized with a peptide substrate for PAD2. The enzyme and different concentrations of calcium ions are flowed through each of eight channels, where the position along the channel corresponds to reaction time and position across the channel corresponds to the concentration of Ca2+. Imaging SAMDI (iSAMDI) is then used to determine the yield for the enzyme reaction at each 200 μm pixel on the monolayer, providing a time course for the reactions. Analysis of the peptide conversion as a function of position and time gives the degree of cooperativity (n) and the concentration of ligand required for half maximal activity (K0.5) for the Ca2+ – dependent activation of PAD2. This work establishes a high‐throughput and label‐free method for studying enzyme‐ligand binding interactions and widens the applicability of microfluidics and matrix‐assisted laser desorption/ionization mass spectrometry (MALDI) imaging mass spectrometry. [ABSTRACT FROM AUTHOR]

Recently, we presented a strategy for packaging peptides as side‐chains in high‐density brush polymers. For this globular protein‐like polymer (PLP) formulation, therapeutic peptides were shown to resist proteolytic degradation, enter cells efficiently and maintain biological function. In this paper, we establish the role charge plays in dictating the cellular uptake of these peptide formulations, finding that peptides with a net positive charge will enter cells when polymerized, while those formed from anionic or neutral peptides remain outside of cells. Given these findings, we explored whether cellular uptake could be selectively induced by a stimulus. In our design, a cationic peptide is appended to a sequence of charge‐neutralizing anionic amino acids through stimuli‐responsive cleavable linkers. As a proof‐of‐concept study, we tested this strategy with two different classes of stimuli, exogenous UV light and an enzyme (a matrix metalloproteinase) associated with the inflammatory response. The key finding is that these materials enter cells only when acted upon by the stimulus. This approach makes it possible to achieve delivery of the polymers, therapeutic peptides or an appended cargo into cells in response to an appropriate stimulus. [ABSTRACT FROM AUTHOR]

Presents research articles on biochemistry to be published in the "European Journal of Biochemistry." "Secondary and Tertiary Structure Characteristic of Megasphaera elsdenii Flavodoxin in the Reduced State as Determined by Two-Dimensional 1H NMR," by C. P. M. van Mierlo, F. M¨ller, and J. Vervoort; "Presence and Characterization of Glycolipid Sulfotransferase in Human Cancer Serum," by S. Gasa, M. -T. Casl, A. Makita, N. Sakakibara, T. Koyanagi, and T. Atsuta; "Interaction of Hemin With Placental Glutathione Transferase," by A. M. Caccuri; A. Aceto, F. Piemonte, C. di Ilio, N. Rosato, and G. Federici.

Introduces several forthcoming articles related to biochemistry to be published in the "European Journal of Biochemistry." "Reactivity of Sulphydryl Groups of the Mitochondrial Phosphate Carrier"; "Raman Spectroscopy and Normal Vibrations of Peptides Characteristic Normal Modes of a Type-II β Turn"; "The Effect of Retinoic Acid on Cyclic-AMP-Binding Proteins in Mouse Melanoma Cells"; "Isolation and Characterization of a Precursor Form of M Collagen From Embryonic Chicken Cartilage."

Purpose: The imaging of intestinal neuroendocrine tumours (NETs) relies on functional positron emission tomography (PET) tracers; these tumours can be studied by means of both 68Ga‐DOTA peptides and 18F‐fluorodihydroxyphenyl‐ l‐alanine (18F‐DOPA) PET/computed tomography (CT). As yet, it is unclear which of these two modalities offers the better sensitivity. We therefore conducted a meta‐analysis to assess the available data. Methods: PubMed, CENTRAL, Scopus and Web of Science were searched for studies comparing the sensitivity of 68Ga‐DOTA peptides and 18F‐DOPA PET/CT; papers up to February 2021 were considered. In each study, we considered sensitivity in terms of patient‐based analysis (PBA), region‐based analysis (RBA) and lesion‐based analysis (LBA), and pooled the results yielded by each tracer. Multidisciplinary follow‐up served as the standard of truth. Results: Of the 636 records identified, 6 articles published between 2008 and 2021 were finally selected, and 112 intestinal NETs patients were included. The pooled sensitivity of 18F‐DOPA PET/CT was 83%, 89% and 95% on PBA, RBA and LBA, respectively. 68Ga‐DOTA peptides PET/CT showed sensitivity of 88%, 92% and 82% on PBA, RBA and LBA, respectively. No significant differences were found between the two tracers on PBA and RBA. By contrast, a clear trend towards significance in favour of 18F‐DOPA PET/CT was identified on LBA. The presence of a significant difference in favour of 18F‐DOPA PET/CT was confirmed in a subgroup analysis conducted only on the most recent and largest studies. In all three analyses, mild‐to‐high heterogeneity was found; however, no publication bias was observed. Conclusion: Both 18F‐DOPA PET/CT and 68Ga‐DOTA‐peptides PET/CT are reliable diagnostic procedures in patients with intestinal NETs. However, in terms of lesion detection, a non‐negligible difference in favour of 18F‐DOPA PET/CT was observed. Thus, the use of 18F‐DOPA PET/CT could be considered as a first‐line molecular procedure in intestinal NETs. [ABSTRACT FROM AUTHOR]

Milk proteins are recognized as the main source of biologically active peptides. Casein's primary structure contains several bioactive amino acid sequences on its latent inactive form. These potential active sequences can be released during cheese manufacture and ripening, giving rise to peptides with biological activity such as antihypertensive, antidiabetic, antioxidant, immunomodulatory, and mineral‐binding properties. However, the presence of biopeptides in cheese does not imply actual biological activity in vivo because these peptides can be further hydrolyzed during gastrointestinal transit. This paper reviews the recent advances in biopeptide formation in ripened cheeses production, focusing on the influence of technological parameters affecting proteolysis and the consequent release of peptides. The main discoveries in the field of cheese peptide digestion through recent in vivo and in vitro model studies are also reviewed. © 2021 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Background: To assess the relationship of chosen salivary proteins and peptides levels with the occurrence of caries in children. Methods: PubMed, MEDLINE and EMBASE databases from 2000 to 2018 were researched for original observational studies published in English. The risk of bias and quality of the included papers were assessed regarding the guidelines by Fowkes and Fulton. Results: Twenty‐two studies were included in the review, from which the issue of glycoproteins (including immunoglobulins), AMPs and salivary enzymes was discussed. The research involved primary dentition (13 papers), as well as mixed (7) and permanent dentition (5). Caries assessment included visual inspection, dmft/s and DMFT/S indexed; quantity of Streptococcus mutans and Lactobacillus spp. bacteria; and caries risk assessment. Discussion: The results of studies regarding the connection between salivary peptides and proteins and caries development in children are promising; however, further investigations should be undertaken. The majority of studies included are case–control and cross‐sectional; however, it is necessary to conduct more cohort studies with adequate follow‐up prior to considering this as markers for caries risk assessment. [ABSTRACT FROM AUTHOR]

Peptide Science publishes peer‐reviewed papers covering all aspects of peptide synthesis, materials, structure and bioactivity. The journal includes both experimental and theoretical studies and serves the interdisciplinary biochemical, biomaterials, biophysical and biomedical research communities. [ABSTRACT FROM AUTHOR]