Enzyme that catalyzes the first step of the tricarboxylic acid cycle (CITRIC ACID CYCLE). It catalyzes the reaction of oxaloacetate and acetyl CoA to form citrate and coenzyme A. This enzyme was formerly listed as EC 4.1.3.7.

Synonyms: Citrate Synthase, Citrate oxaloacetate-lyase ((pro-3S)-CH2COO(-)--acetyl-CoA), EC 2.3.3.1, Synthase, Citrate, Citrate (si)-Synthase