The Enzymic Interconversion of Isobutyryl and <i>n</i>‐Butyrylcarba(dethia)‐Coenzyme A: A Coenzyme‐B₁₂‐dependent Carbon Skeleton Rearrangement

Abstract

The synthetic carba(dethia) analogues of coenzyme A contain a —CO—CH2—instead of a —CO—S— group and are therefore hydrolytically stable. The isobutyrylcarba(dethia) coenzyme A 1, whose synthesis is reported here, is isomerized to the n-butyryl derivative 2 by a cell extract from Streptomyces cinnamonensis (monitored by 1H NMR). This new, coenzyme B12-dependent structural rearrangement is similar in many ways to the long-known methylmalonyl-CoA mutase reaction.