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Abstract: Natto-red bean with fibrinolytic activity was prepared by fermenting red beans with Bacillus subtilis. A fibrinolytic enzyme was purified from fermented natto-red bean by sequential steps of ammonium sulfate fractionation, Sephacryl S-200 HR gel filtration and PBE 94 chromatofocusing. Through these steps, the purity of the enzyme increased 291-fold with 1.5% activity recovery. SDS–PAGE and isoelectric focusing electrophoresis showed the molecular mass and pI of the purified enzyme to be 29.93kDa and 6.35, respectively. When N-succinyl-Ala-Ala-Pro-Phe-ρNA was used as an enzyme substrate, the K m, V max, and optimal reaction pH and temperature were 0.59mM, 79.4μmole ρNA/minmg, 9 and 60°C, respectively. Among the synthetic substrates, the most sensitive were N-succinyl-Ala-Ala-Pro-Phe-ρNA, followed by N-benzoyl-Val-Gly-Arg-ρNA. Chemical modifiers, such as phenylmethyl sulfonyfluoride, N-bromosuccinimide and N-ethyl-5-phenylisoxazolium-3′-sulfonate, almost completely inhibited the activity of the purified enzyme. These results indicated that the purified fibrinolytic enzyme was a subtilisin-like serine protease. [Copyright &y& Elsevier]

Abstract: This study investigated the effects of low molecular weight chitosan (LMWC) on the renal functions for aristolochic acid (AA)-induced renal lesions in C3H/He mice. Commercial crab shell chitosan (molecular mass of ∼1100kDa) was hydrolysed using bamboo chitosanase at pH 3.5 and 50°C for 18h. LMWC (with molecular mass of ∼29kDa) was isolated from the hydrolysate through 50% methanol fractionation. The levels of urinary microalbumin, urinary-N-acetyl-beta-d-glucosaminidase, serum creatinine, and blood urea nitrogen were higher in the AA induced mice than those in the control group, while the rate for creatinine clearance was lower in the AA induced mice. Oral administration of LMWC could suppress the elevation of urinary and blood nitrogen concentrations induced by AA treatment. Renal histopathological examination revealed that AA-induced renal alterations were reverted effectively by the treatment of LMWC at three tested doses, especially at the moderate dose of 500mg/kg BW. [Copyright &y& Elsevier]

Abstract: This study aimed to evaluate the inhibition properties of six lavender species, including Lavendula angustifolia, Lavandula angustifolia “Vera”, Lavendula X allardii, Lavendula stoechas, Lavendula viridis and Lavendula X heterophylla, toward the activity of mushroom tyrosinase. When using l-3,4-dihydroxyphenylalanine (l-Dopa) as the substrate for mushroom tyrosinase, the water extracts of leaves and stems from L. stoechas and L. angustifolia “Vera” showed strong inhibitory effects against the activity of mushroom tyrosinase (70% and 66.4% inhibition, respectively). Oven-drying the leaves and stems or free-drying the water extracts significantly decreased the inhibitory abilities of the water extracts from all lavender species. The water extract from L. stoechas decreased the V max values when using l-Dopa, catechol and 3,4-dihydroxyphenylacetic acid (DHPAA) as the substrates. It increased the value of K m when l-Dopa and catechol were the substrates but it decreased the K m when DHPAA was used. It behaved as a mixed-type inhibitor toward mushroom tyrosinase. [Copyright &y& Elsevier]

Abstract: This study was aimed at evaluating the kinetic properties and capacities of water (GWE), 50% ethanolic (GE50) and 95% ethanolic (GE95) extracts from Graptopetalum paraguayense for the potential to inhibit angiotensin converting enzyme (ACE). The results showed that GWE, GE50 and GE95 showed potent inhibitory effects on ACE. It was found that the ACE inhibitory activities of all the tested extracts increased with the increase of their concentrations. In addition, the ACE inhibition of the tested extracts of G. paraguayense were significantly reduced after the addition of 1.5mM ZnCl2, suggesting the inhibitory action of the extracts may have resulted from the chelation of the ACE zinc cofactor. The inhibition kinetics, analyzed by Lineweaver–Burk plots, revealed that G. paraguayense extracts showed a mixed-type inhibition. A comparison of the 50% inhibition concentration (IC50) and K i values showed that the ethanolic extracts, including GE50 and GE95 exhibited the more effective ACE inhibitory activity than the water extracts of G. paraguayense. [Copyright &y& Elsevier]

Abstract: An acidic peroxidase isoform, POD-A, with a molecular mass of 69.4kDa and an isoelectric point of 3.5 was purified from papaya latex. Using o-phenylenediamine (OPD) as a hydrogen donor (citrate–phosphate as pH buffer), the optimum pH for the function of POD-A was 4.6, and the optimum temperature was 50°C. The peroxidase activity of POD-A toward hydrogen donors was both pH- and concentration-dependent. Under optimal conditions, POD-A catalysed the oxidation of OPD at higher rates than pyrogallol, catechol, quercetin and 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS). The chemical modification reagents N-bromosuccinimide and sodium azide significantly inhibited POD-A activity. The results of kinetic studies indicated that POD-A followed a ping-pong mechanism and had a K m value of 2.8mM for OPD. Using CPC silica-immobilised POD-A for the determination of micromolar H2O2 in milk, the lower limit of determination was 0.1μM, and the recoveries of added H2O2 were 96–109%. [Copyright &y& Elsevier]

Abstract: An alkaline invertase (IT I) and an acid invertase (IT II) were purified from the soluble fraction of suspension cultured bamboo cells. Both purified invertases were homogeneous as examined by SDS–polyacrylamide gel electrophoresis (SDS–PAGE) and were identified as β-fructofuranosidases able to attack the β-fructofuranoside from the fructose end. With respect to sucrose hydrolysis, the optimal pHs were 7.0 and 4.5 for IT I and IT II, respectively. The Km’s were 10.9 and 3.7mM. The IT I and IT II molecular masses were 240 and 68kDa, respectively, as estimated by gel filtration. The isoelectric points were 4.8 and 7.4. IT I was a homotetrameric enzyme activated by bovine serum albumin (BSA). IT II was a monomeric enzyme activated by BSA, concanavalin A (ConA) and urease. Both isoforms were significantly inhibited by heavy metal ions Ag+ (5mM) and Hg2+ (1mM), and mercaptide forming agent ρ-chloromercuribenzoic acid (PCMB; 0.5mM). [Copyright &y& Elsevier]

This study was aimed to evaluate the kinetic properties and capacities of 95% ethanolic (GE95), 50% ethanolic (GE50) and water (GWE) extracts from Graptopetalum paraguayense for their potential to inhibit mushroom tyrosinase activity. The results showed that GE95, GE50 and GWE showed potent inhibitory effects on l-3,4-dihydroxyphenylalanine (l-Dopa) oxidation catalyzed by tyrosinase. It was found that the tyrosinase inhibitory activities of all the extracts increased with the increase of their concentrations. The inhibition kinetics, analyzed by Lineweaver–Burk plots, revealed that G. paraguayense extracts showed a mixed-type inhibition for mushroom tyrosinase when l-Dopa was used as substrate. A comparison of the IC50 and Ki values showed that GE95 exhibited the most effective inhibition of tyrosinase among the extracts. [Copyright &y& Elsevier]

Abstract: A β-N-acetylhexosaminidase (β-NAHA) (EC 3.2.1.52) with molecular mass of 64.1kDa and isoelectric point of 5.5 was purified from a commercial papaya latex preparation. The optimum pH for p-nitrophenyl-N-acetyl-β-d-glucosaminide (pNP-β-GlcNAc) hydrolysis was five; the optimum temperature was 50°C; the K m was 0.18mM, V max was 37.6μmolmin−1 mg−1 and activation energy (E a) was 10.3kcal/mol. The enzyme was thermally stable after holding at 30–45°C for 40min, but its activity decreased significantly when the temperature exceeded 50°C. Heavy metal ions, Ag+ and Hg2+, at a concentration of 0.25mM and Zn2+ and Cu2+, at a concentration of 0.5mM, significantly inhibited enzyme activity. The β-NAHA had only one active site for binding both pNP-β-GlcNAc and p-nitrophenyl-N-acetyl-β-d-galactosaminide (pNP-β-GalNAc). A prototropic group with pKa value of about five on the enzyme may be involved in substrate binding and transformation, as examined by Dixon–Webb plots. [ABSTRACT FROM AUTHOR]

Abstract: This study was aimed to evaluate the antioxidative activities of water (GWE), 50% ethanolic (GE50), and 95% ethanolic (GE95) extracts of Graptopetalum paraguayense. The antioxidant activities, including the radical-scavenging effect, reducing power, and antioxidative effect on Fe/ascorbate-induced lipid peroxidation in a liposome model system, were studied in vitro. The results showed that GWE, GE50 and GE95 possessed antioxidant characteristics including radical scavenging, reducing power, and lipid peroxidation inhibition. It was found that the antioxidative activities of all the extracts increased with increasing concentrations, and the activities correlated with both the total phenol and anthocyanin contents. A comparison of the 50% inhibition concentration (IC50) values of different antioxidative reactions revealed that GE50 was more effective in scavenging α,α-diphenyl-β-picrylhydrazyl (DPPH) radical and showed a higher reducing power than GWE and GE95. However, there were no significant differences (P>0.05) in the lipid peroxidation-prevention effects among the extracts. [Copyright &y& Elsevier]