Cephalosporin-C transaminase () is an enzyme that catalyzes a reversible chemical reaction which interconverts a D-amino acid with the corresponding α-keto acid. The amino group is transferred to α-ketoglutaric acid, giving L-glutamic acid. Unlike D-amino-acid transaminase, which can also use D-amino acids such as D-alanine as substrates, cephalosporin-C transaminase has high activity with the β-lactam antibiotic, cephalosporin C. In that case, the product keto acid has the chemical name (7R)-7-(5-carboxy-5-oxopentanoyl)aminocephalosporinate.
Formally, the enzyme is a transferase, specifically a transaminase, which transfer nitrogenous groups. The systematic name of this enzyme class is cephalosporin-C:2-oxoglutarate aminotransferase. Other names in common use include cephalosporin C aminotransferase, and L-alanine:cephalosporin-C aminotransferase.
It has been suggested that this reaction could be used as part of a sequence of enzyme-cataylsed reactions to remove the sidechain of cephalosporin C and produce 7-aminocephalosporanic acid, for conversion into other commercial antibiotics.
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