Epoxide formation in the enzymic conversion of [4-2H]exomethylene cephalosporin C by deacetoxy-/deacetylcephalosporin C synthase

Abstract

The use of a deuterium kinetic isotope effect has enabled the isolation and characterisation of a novel epoxide metabolite produced in the enzymic conversion of [4-²H]exomethylene cephalosporin C into deacetylcetylcephalosporin C catalysed by the enzyme deacetoxycephalosporin C/deacetylcephalosporin C synthase; V_max/K_m experiments are also described, which suggest that the first irreversible event in the conversion of exomethylene cephalosporin C does not involve C-4 hydrogen abstraction.