Cleavage of the 5-amino-5-carboxy-2-oxapentanoyl side chain from enzymatically synthesised penicillins and cephalosporins

Both 5R- and 5S-5-amino-5-carboxy-2-oxapentanoyl side chains can substitute for the L-δ-α-aminoadipoyl side chain in the isopenicillin N synthase catalysed formation of penicillins from tripeptides. The 5R- side chain analogue can be cleaved from penicillins and cephalosporins by treatment with D-amino acid oxidase followed by oxidative decarboxylation and decarboxylative elimination.