Complete Stereochemistry of the Enzymatic Dehydration of 4-Hydroxybutyryl Coenzyme A to Crotonyl Coenzyme A

The stereospecific action of the microbial enzyme 4‐hydroxybutyryl‐CoA dehydratase on the three prochiral centers of its substrate 4‐hydroxybutyryl‐CoA can now be described as anti elimination of the 2Re and 3Si hydrogen atoms with retention of configuration during the substitution of the hydroxy group by a hydrogen atom. The results confirm the relationship of the dehydratase to acyl‐CoA dehydrogenases and the view that the Fe4S4 cluster acts as a Lewis acid.