02266nas a2200241   4500008004100000022001400041245011000055210006900165260007300234300000800307490000700315520137800322653001601700653002001716653001801736653002501754653002501779100002901804700002601833700001901859700002001878856012601898       2015                        eng d  a0141-813000aPenicillin V acylase from pectobacterium atrosepticum exhibits high specific activity and unique kinetics0 aPenicillin V acylase from pectobacterium atrosepticum exhibits h  aPO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSbELSEVIER SCIENCE BVcAUG  a1-70 v793 a<p>Penicillin V acylases (PVAs, E.C.3.5.11) belong to the Ntn hydrolase super family of enzymes that catalyze the deacylation of the side chain from phenoxymethyl penicillin (penicillin V). Penicillin acylases find use in the pharmaceutical industry for the production of semi-synthetic antibiotics. PVAs employ the N-terminal cysteine residue as catalytic nucleophile and are structurally and evolutionarily related to bile salt hydrolases (BSHs). Here, we report the cloning and characterization of a PVA enzyme from the Gram-negative plant pathogen, Pectobacterium atrosepticum (PaPVA). The enzyme was cloned and expressed in Escherichia coli attaining a very high yield (250 mg/l) and a comparatively high specific activity (430 IU/mg). The enzyme showed marginally better pH and thermo-stability over PVAs characterized from Gram-positive bacteria. The enzyme also showed enhanced activity in presence of organic solvents and detergents. The enzyme kinetics turned out to be significantly different from that of previously reported PVAs, displaying positive cooperativity and substrate inhibition. The presence of bile salts had a modulating effect on PaPVA activity. Sequence analysis and characterization reveal the distinctive nature of these enzymes and underscore the need to study PVAs from Gram-negative bacteria. (C) 2015 Elsevier B.V. All rights reserved.</p>10aCooperative10aEnzyme kinetics10aGram-negative10aPenicillin V acylase10aSubstrate inhibition1 aAvinash, Vellore, Sunder1 aRamasamy, Sureshkumar1 aSuresh, C., G.1 aPundle, Archana  uhttps://library.ncl.res.in/content/penicillin-v-acylase-pectobacterium-atrosepticum-exhibits-high-specific-activity-and-002331nas a2200241   4500008004100000022001400041245010100055210006900156260009900225300001200324490000700336520143200343653002601775653001501801653002401816653002001840653001701860653002501877100001801902700002601920700001901946856012401965       2016                        eng d  a1359-511300aHighly active bile salt hydrolase from enterococcus faecalis shows positive cooperative kinetics0 aHighly active bile salt hydrolase from enterococcus faecalis sho  aTHE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLANDbELSEVIER SCI LTDcFEB  a263-2690 v513 a<p>Bile salt hydrolase (BSH; cholylglycine hydrolase, EC 3.5.1.24) is an important enzyme that catalyses the deconjugation of bile acids conjugated with glycine or taurine and assists in the reduction of blood cholesterol levels. In the present study, we report the cloning, overexpression and characterisation of BSH gene from a gut-associated microbe Enterococcus faecalis (EfBSH). The overexpressed protein in Escherichia coli was purified to homogeneity. Optimum pH and temperature for activity were found to be 5.0 and 50 degrees C, respectively. The enzyme was considerably stable in the pH range of 5.0-7.0 and at a temperature of up to 50 degrees C. It showed high specific activity of 1390 U mg(-1) and 1289 U mg-1 for substrates such as glycocholic acid (GCA) and glycodeoxycholic acid (GDCA), respectively. The effect of additives on enzyme activity was assessed, and the detergent Triton X showed a marginally enhanced activity. The enzyme demonstrated unique enzyme kinetics of non-linear regression, thereby displaying positive cooperativity. In addition, the modulating effect of the non-substrate ligand Pen V on the hydrolysing ability of EfBSH towards bile acid such as GDCA was measured. It was observed that Pen V significantly enhanced the BSH activity. This is markedly different from the previously reported competitive inhibition of BSH activity by Pen V. (C) 2015 Elsevier Ltd. All rights reserved.</p>10aAllosteric regulation10aBile acids10aBile salt hydrolase10aEnzyme kinetics10aGut organism10aPenicillin V acylase1 aChand, Deepak1 aRamasamy, Sureshkumar1 aSuresh, C., G.  uhttps://library.ncl.res.in/content/highly-active-bile-salt-hydrolase-enterococcus-faecalis-shows-positive-cooperative-0