 These enzymes share a 3-layer alpha-beta-alpha structure, and play important roles in arginine/agmatine metabolism, the urea cycle, histidine degradation, and other pathways.Arginase, which catalyses the conversion of arginine to urea and ornithine, is one of the five members of the urea cycle enzymes that convert ammonia to urea as the principal product of nitrogen excretion.There are several arginase isozymes that differ in catalytic, molecular and immunological properties.