Ornithine Transcarbamylase (OTC)

Ornithine transcarbamoylase (OTC) (also called ornithine carbamoyltransferase) is an enzyme that catalyzes the reaction between carbamoyl phosphate (CP) and ornithine (Orn) to form citrulline (Cit) and phosphate (P_i). In plants and microbes OTC is involved in arginine (Arg) biosynthesis, whereas in mammals it is located in the mitochondria and is part of the urea cycle.OTC is a trimer.

The monomer unit has a CP-binding domain and an amino acid-binding domain. Each of the two discrete substrate-binding domains (SBDs) have an alpha/beta; topology with a central beta-pleated sheet embedded in flanking alpha-helices.The active sites are located at the interface between the protein monomers.