@article { ISI:000359166300001,
	title = {Penicillin V acylase from pectobacterium atrosepticum exhibits high specific activity and unique kinetics},
	journal = {International Journal of Biological Macromolecules},
	volume = {79},
	year = {2015},
	month = {AUG},
	pages = {1-7},
	publisher = {ELSEVIER SCIENCE BV},
	address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS},
	abstract = {<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>},
	keywords = {Cooperative, Enzyme kinetics, Gram-negative, Penicillin V acylase, Substrate inhibition},
	issn = {0141-8130},
	doi = {10.1016/j.ijbiomac.2015.04.036},
	author = {Avinash, Vellore Sunder and Ramasamy, Sureshkumar and Suresh, C. G. and Pundle, Archana}
}
@article { ISI:000370100200012,
	title = {Highly active bile salt hydrolase from enterococcus faecalis shows positive cooperative kinetics},
	journal = {Process Biochemistry},
	volume = {51},
	number = {2},
	year = {2016},
	month = {FEB},
	pages = {263-269},
	publisher = {ELSEVIER SCI LTD},
	address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND},
	abstract = {<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>},
	keywords = {Allosteric regulation, Bile acids, Bile salt hydrolase, Enzyme kinetics, Gut organism, Penicillin V acylase},
	issn = {1359-5113},
	doi = {10.1016/j.procbio.2015.12.006},
	author = {Chand, Deepak and Ramasamy, Sureshkumar and Suresh, C. G.}
}
