Thioester
- The sulfur variant of an ester
It is an ester with a sulfur atom in place of the single-bonded oxygen.
Thioesters are intermediates in a number of biosynthetic reactions, including the formation and degradation of fatty acids and steroids. The most commonly known thioester is acetyl CoA, the ester form of coenzyme A, which plays a major role in the Krebs cycle (as does coenzyme A, described previously).