Penicillin G amidohydrolase

E.C. 3.5.1.4) used to prepare amino acids, usually through resolution, and also penicillin G acylase (penicillin G amidohydrolase) (E.C. 3.5.1.11), used in the manufacture of semisynthetic penicillins.152 153 Immobilized penicillin G acylase has most recently been used to catalyze the formation of. V-a-phenylacetyl amino acids, which can then be used in peptide coupling reactions (see Section 19.2.3.2).154 Bacterial aminoacylase I (.V-acyl-i.-amino acid amidohydrolase, E.C. 3.5.1.14) has also been used to acylate chiral amines with poor to moderate enantioselectively.155... 

The beta-amino acid, (S)-ethyl 3-amino-4-pentynoate, a chiral synthon, was an intermediate in the synthesis of an anti-platelet agent, xemilofiban. A biocatalytic process using the enzyme Penicillin G amidohydrolase was developed to resolve (R)-and (S)-enantiomers of ethyl 3-amino-4-pentynoate in enantiomerically pure form. The design of experimental approach used was one to optimize the critical reaction parameters to control the stereoselectivity of the enzyme Penicillin G amidohydrolase. 

As a part of ongoing efforts to synthesize a potent, orally active anti-platelet agent, xemilofiban 1 [1], development of an efficient chemoenzymatic process for 2, the chiral yS-amino acid ester synthon (Fig. 1) was proposed. The scheme emphasized the creation of the stereogenic center as the key step. In parallel with the enzymatic approach, chemical synthesis of the / -amino acid ester synthon emphasized formation of a chiral imine, nucleophilic addition of the Reformatsky reagent, and oxidative removal of the chiral auxiliary. This chapter describes a selective amida-tion/amide hydrolysis using the enzyme Penicillin G amidohydrolase from E. coli to synthesize (R)- and (S)-enantiomers of ethyl 3-amino-5-(trimethylsilyl)-4-pen-tynoate in an optically pure form. The design of the experimental approach was applied in order to optimize the critical reaction parameters to control the stereoselectivity of the enzyme Penicillin G amidohydrolase. 

Penicillin G amidohydrolase (PGA) (E.C. 3.5.1.11) from E. coli ATCC 9637 is a unique enzyme that exhibits exceptionally high affinity to phenylacetic acid and its derivatives [2], This capability has been used advantageously to achieve moder-... 

The commercial supply is primarily derived from expressing the enzyme Penicillin G amidohydrolase (E.C. 3.5.1.11) ATCC 9637 in E. coli. Soluble enzyme was obtained from Calbiochem and Boehringer-Mannheim, and immobilized enzyme was obtained from Sigma, Rohm-Pharma and Boehringer-Mannheim. The recovery of the immobilized enzyme made it cost effective compared with the soluble enzyme. 

Penicillin G amidohydrolase proved to be an effective and efficient catalyst for en-antioselective acylation as well as deacylation. Synthesis of the desired antipode [(R)- or (S)-enantiomer] can be achieved by selecting either amidation or amide hy-... 

Penicillin acylases or amidohydrolases, which cleave the amide side chain of penicillin G, have been known for almost 50 years. " As one of the first enzymes to be developed for use at scale in the pharmaceutical industry, penicillin G acylase (PGA) has often been used as a model system for academic studies from molecular biology to biochemical engineering. Despite extensive screening, however, for decades there was no equivalent enzyme to generate 7-ACA by cleaving the polar D-a-aminoadipoyl side chain from cephalosporin C. 

Penicillin G acylase (benzylpenicillin amidohydrolase, also named penicillin amidase EC 3.5.1.11) is an enzyme used commercially to produce 6-aminopenicillanic add (6-APA), the most important intermediate for the industrial production of semisynthetic penicillins. This is achieved by the hydrolysis of penicillin G (for review, see Bruggink et al. 1998,0 Fig. 6.6, left column). 

Penicillin and related antibiotics are inactivated by P-lactamases (Box 20-G), some of which resemble serine proteases in forming acyl enzymes with active site serine side chains.656 657 Others are zinc metallogen-zymes.658/659 Amidohydrolases such as asparaginase and glutaminase,660/661 deacetylases,662 and many other hydrolases can also be described as acyltransferases. 

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