Topic
Penicillin amidase
About: Penicillin amidase is a research topic. Over the lifetime, 576 publications have been published within this topic receiving 15563 citations. The topic is also known as: penicillin amidohydrolase & ampicillin acylase.
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TL;DR: Different carrier-free and carrier-bound penicillin acylases were evaluated in the thermodynamically controlled enzymatic synthesis in organic medium of deacetoxycephalosporin G using phenylacetic acid and 7-amino-deacetoxycefalosporanic acid used as a model reaction system.
14 citations
TL;DR: Immobilized cells of Alcaligenes sp.
Abstract: Isolation and characterization of a β-lactamase (EC 3.5.2.6)-free, penicillin amidase (penicillin amidohydrolase, EC 3.5.1.11)-producing organism is reported. The test strain was isolated by an enrichment technique with a substrate other than penicillins. The isolated strain belongs to the genus Alcaligenes. Phenylacetic acid was found to be the inducer of penicillin amidase. The amidase has a broad substrate spectrum. It is very active against penicillin G and semisynthetic cephalosporins, whereas penicillin V and semisynthetic penicillins acted moderately as a substrate. Immobilized cells of Alcaligenes sp. were shown to act as a reversible enzyme.
14 citations
TL;DR: It was shown that the processing rates of wild-type and mutant precursor PAs depended on the pKa values of their side chain R group, and it was demonstrated that the lysine residue (K299) was involved in the precursor processing of PA together with N-terminal serine residue of the large subunit.
14 citations
TL;DR: Structural data is presented that pertain to the unanswered questions that arose from the original strucutre of Penicillin Gacylase from Escherichia coli, and mutations that allow processing but yield inactive protein provide the structure of an ES complex with a true substrate.
Abstract: Penicillin acylases are used in the pharmaceutical industry for the preparation of antibiotics. The 3-D structure of Penicillin G acylase from Escherichia coli has been solved. Here, we present structural data that pertain to the unanswered questions that arose from the original strucutre. Specificity for the amide portion of substrate was probed by the structure determination of a range of complexes with substitutions around the phenylacetyl ring of the ligand. Altered substrate specificity mutations derived from an in vivo positive selection process have also been studied, revealing the structural consequences of mutation at position B71. Protein processing has been analyzed by the construction of site-directed mutants, which affect this reaction with two distinct phenotypes. Mutations that allow processing but yield inactive protein provide the structure of an ES complex with a true substrate, with implications for the enzymatic mechanism and stereospecificity of the reaction. Mutations that preclude processing have allowed the structure of the precursor, which includes the 54 amino acid linker region normally removed from between the A and B chains, to be visualized. Index Entries: Penicillin acylase; 3-D structures; site-directed mutagenesis; substrate binding; autocatalytic processing; precursor.
14 citations
TL;DR: The computation approach revealed to be helpful in elucidating the molecular basis of the enantioselectivity observed on PGA-CSP and its influence on pharmacological activity was investigated by application of molecular modelling studies.
14 citations