Might regulate the synthesis and function of enzymes involved in later enzymatic steps of Krebs cycle. acetyl-CoA + H2O + oxaloacetate = citrate + CoA + H(+) Carbohydrate metabolism; tricarboxylic acid cycle; isocitrate from oxaloacetate: step 1/2. Homodimer. When expressed in E.coli, CitZ is produced in a soluble but inactive form that can be reactivated by incubating with 2 M KCl (PubMed:10397837). Citrate synthase is found in nearly all cells capable of oxidative metabolism. Belongs to the citrate synthase family.