Stereochemical course of the hydration reaction catalysed by β-hydroxydecanoylthioester dehydrase

Enzyme-catalysed hydration of the N-acetylcysteamine thioester of (E)-dec-2-enoic acid to the corresponding thioester of (R)-3-hydroxydecanoic acid proceeds in a syn fashion, with protonation on the si face at substrate C-2.