Psorn inhibits ornithine carbamoyltransferase (OCTase) an ornithine cycle citrulline.Ornithine therefore accumulates in the tissues and arginine and cutrulline biosynthesis is blocked.

• 抑制鸟氨酸氨磺酰基转移酶，从而抑制了精氨酸和瓜氨酸的合成。