Ornithine transcarbamylase protein homotrimers bind zinc; however, the specific impact of zinc deficiency on enzyme activity in vivo is not clear and could potentially be related to a role in bridging or clustering of the proximal urea cycle enzymes (N‐acetylglutamate synthase, carbamoyl phosphate synthetase I, and ornithine transcarbamylase) on the mitochondrial inner membrane [21]. The gene discussed is CPS1; the disease is Zinc deficiency.