acetyl-CoA + H2O + oxaloacetate = citrate + CoA + H(+) Carbohydrate metabolism; tricarboxylic acid cycle; isocitrate from oxaloacetate: step 1/2. Homodimer. Expressed in the head region and flagellum of epididymal sperm. Methylated. Trimethylation at Lys-395 by CSKMT decreases citrate synthase activity. Citrate synthase is found in nearly all cells capable of oxidative metabolism. Belongs to the citrate synthase family.