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Publication Abstract from PubMed

BACKGROUND: Semisynthetic cephalosporins are primarily synthesized from 7-aminocephalosporanic acid (7-ACA), which is obtained by environmentally toxic chemical deacylation of cephalosporin C (CPC). Thus, the enzymatic conversion of CPC to 7-ACA by cephalosporin acylase (CA) would be of great interest. However, CAs use glutaryl-7-ACA (GL-7-ACA) as a primary substrate and the enzyme has low turnover rates for CPC. RESULTS: The binary complex structures of CA with GL-7-ACA and glutarate (the side-chain of GL-7-ACA) show extensive interactions between the glutaryl moiety of GL-7-ACA and the seven residues that form the side-chain pocket. These interactions explain why the D-alpha-aminoadipyl side-chain of CPC yields a poorer substrate than GL-7-ACA. CONCLUSIONS: This understanding of the nature of substrate specificity may be useful in the design of an enzyme with an improved performance for the conversion of CPC to 7-ACA. Additionally, the catalytic mechanism of the deacylation reaction was revealed by the ligand bound structures.

Structure of cephalosporin acylase in complex with glutaryl-7-aminocephalosporanic acid and glutarate: insight into the basis of its substrate specificity.,Kim Y, Hol WG Chem Biol. 2001 Dec;8(12):1253-64. PMID:11755403^[2]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.