Arginase is a manganese metalloenzyme that catalyzes the conversion of L-arginine to L-ornithine and urea. It is found in bacteria, yeasts, plants, invertebrates and vertebrates, and is thought to have appeared first in bacteria. The cytosolic and mitochondrial arginase isoenzymes are named A1 and A2, respectively. The mitochondrial A2 isoform is thought to be derived from the ancestral arginase, because A1 is restricted to a subset of more recently evolved species.Enhanced arginase activity and the resultant decreases in L-arginine levels can also impair T cell-mediated immune function and allow tumor growth by limiting the supply of L-arginine needed for formation of cytotoxic levels of NO by iNOS. Increased arginase expression/activity may also limit iNOS expression through reducing L-arginine required for iNOS translation.Upregulation of arginase expression and activity has been demonstrated in many diseases characterized by cardiovascular dysfunction, but is only recently been recognized as a potential mediator of neurovascular disease and injury in the CNS. 


1.Caldwell RB,et al. Trends Pharmacol Sci. 2015 Jun;36(6):395-405.