Topic overview

Start with the big picture

Thioesters link an acyl group to sulfur, while acyl phosphates connect it to phosphate through an anhydride bond. In both, weaker resonance stabilization increases the electrophilic character of the carbonyl carbon. Nucleophilic attack forms a tetrahedral intermediate, followed by departure of a stabilized leaving group: thiolate or phosphate. Hydrolysis of these compounds can release energy that helps drive otherwise unfavorable biosynthetic steps or support ATP formation. Acetyl-CoA is a central acyl carrier, and other thioesters include succinyl-CoA and fatty acyl-CoA. Acyl phosphates such as 1,3-bisphosphoglycerate and acetyl phosphate participate in energy metabolism. The lesson connects these structures and mechanisms to their biological uses.