Please use this identifier to cite or link to this item: http://hdl.handle.net/10603/2599
Title: Investigation into the structure and activity of conjugated bile salt hydrolase and related penicillin acylase
Researcher: Sureshkumar, R
Guide(s): Suresh, C G
Keywords: Biochemical, X-Ray
Upload Date: 2-Sep-2011
University: University of Pune
Completed Date: November, 2006
Abstract: The Penicillin acylases are used in the commercial production of 6-amino penicillanic acid (6-APA), the starting compound for the synthesis of semi-synthetic penicillins. The enzyme bile salt hydrolase (BSH) is related to penicillin V acylase and has potential application in lowering the serum cholesterol level in hypercholestremic humans or to prevent hypercholesterolemia in individuals with normal cholesterol. We report in this thesis the extensive studies carried out on a bile salt hydrolase (Cholylglycin hydrolase, EC 3.5.1.24) from Bifidobacterium longum ( BlBSH) and two penicillin G acylases (PGAs) (penicillin amidohydrolase, EC 3.5.1.11) from Kluyvera citrophila (KcPGA) and Alcaligence faecalis (AfPGA). These enzymes could be placed in N-terminal nuleophile (Ntn) hydrolase superfamily. Ntn hydrolases are a class of enzymes that share a common fold of áââá- core structure possessing a N-terminal catalytic nucleophile residue. In BSH the N-terminal nucleophile is cysteine while in PGAs it is serine. The Ntn hydrolases invariably produce their active form from the corresponding precursor by an intra-molecular autocatalytic cleavage to create a free amino group at the nucleophile residue. Bile salt hydrolase (BSH) catalyses the hydrolysis of glycine or taurine conjugated bile salt into the corresponding amino acid residues and the deconjugated bile salt. The ability to deconjugate bile salts is widespread among the members of the genus Bifidobacterium. The deconjugation of six different salts by all bifidobacteria strains that inhabit animal gut is one way of transforming the bile salt in intestine. In recent years therapeutic use of bile salt deconjugation by lactic acid bacteria to lower serum cholesterol level is being tried. Penicillin acylases, a subclass of -lactam antibiotic acylase superfamily, catalyze the selective hydrolysis of relatively stable amide bond in penicillins and some cephalosporins while leaving the labile -lactam ring intact. The capacity of penicillin G acylases to catalyze the acylation of amino group of key intermediates can be used in the environment-friendly synthesize of semi-synthetic -lactam antibiotics. PGAs are also useful for other applications such as peptide synthesis, removal of protecting groups and separation of racemic mixtures of certain compounds.
Pagination: 315p.
URI: http://hdl.handle.net/10603/2599
Appears in Departments:National Chemical Laboratory

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01_title.pdfAttached File3.4 MBAdobe PDFView/Open
02_declaration.pdf3.4 MBAdobe PDFView/Open
03_certificate.pdf3.4 MBAdobe PDFView/Open
04_dedication.pdf3.4 MBAdobe PDFView/Open
05_acknowledgements.pdf3.4 MBAdobe PDFView/Open
06_contents.pdf3.41 MBAdobe PDFView/Open
07_list of abbreviations.pdf3.41 MBAdobe PDFView/Open
08_abstract.pdf3.41 MBAdobe PDFView/Open
09_chapter 1.pdf3.49 MBAdobe PDFView/Open
10_chapter 2.pdf3.48 MBAdobe PDFView/Open
11_chapter 3.pdf3.48 MBAdobe PDFView/Open
12_chapter 4.pdf3.56 MBAdobe PDFView/Open
13_chapter 5.pdf3.52 MBAdobe PDFView/Open
14_chapter 6.pdf3.6 MBAdobe PDFView/Open
15_chapter 7.pdf3.43 MBAdobe PDFView/Open
16_chapter 8.pdf3.46 MBAdobe PDFView/Open
17_conclusion.pdf3.4 MBAdobe PDFView/Open
18_appendix.pdf3.44 MBAdobe PDFView/Open
19_references.pdf3.5 MBAdobe PDFView/Open


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