Catalyzes the second step of the urea cycle, the condensation of carbamoyl phosphate with L-ornithine to form L-citrulline (PubMed:7332529). The urea cycle ensures the detoxification of ammonia by converting it to urea for excretion (Probable). carbamoyl phosphate + L-ornithine = H(+) + L-citrulline + phosphate Inhibition by ornithine increases at higher pH. With an increase in pH, a decrease in KM values for ornithine and an increase in the extent of inhibition by ornithine are observed. Optimum pH is 7.5 in the presence of 5 mM ornithine. The curve shifts toward a more alkaline region with a decrease in ornithine concentration. Nitrogen metabolism; urea cycle; L-citrulline from L-ornithine and carbamoyl phosphate: step 1/1. Homotrimer. Expressed in kidney, brain, heart, liver, pancreas, gizzard, small intestine and breast muscle. More abundant in mitochondrion-rich organs (heart, liver and brain) than in other organs. Activity is only detected in the kidney. Activity detectable in embryos by day 14. Increases until 7 days post-hatching, then decreases again. By diet of egg yolk in animals which have a high level of OTC activity due to presence of OCB gene. Cleavage of the precursor form to the active form occurs only in the kidney. Ornithine transcarbamylase activity varies within and between different breeds of chicken. Belongs to the aspartate/ornithine carbamoyltransferase superfamily. OTCase family.