Arginase is an enzyme that metabolizes L-arginine into L-ornithine and urea, and is associated with endothelial dysfunction and aging, which have two isoforms, namely arginase 1 (Arg1) and arginase 2 (Arg2), with Arg2 being the predominant isoform induced in human ECs’ mitochondria (Yang and Ming, 2013; Yepuri et al., 2012; Jenkinson et al., 1996). The gene discussed is ARG2; the disease is endothelial dysfunction.