acylmercaptan bond

ac·yl·mer·cap·tan bond

A "high-energy" bond formed by the condensation of a carboxyl group (-COOH) and a mercaptan (or thiol) group (-SH); widely formed in the course of intermediary metabolism, notably in the oxidation of fats, where the -SH is part of coenzyme A and the -COOH is part of the fatty acid being oxidized.