The article describes arginase’s role in pathogenesis of endothelial dysfunction and a number of cardio-vascular diseases. Arginase catalyzes the hydrolysis of L-arginine, the substrate for nitric oxide synthesis, to L-ornithine and urea. Two isoforms of arginase were found in the human organism. Arginase I is located in the cells cytoplasm and is predominantly expressed in the liver. Arginase II is a mitochondrial protein that is expressed in the kidney, prostatic gland and vascular wall. Arginase II hydrolyzes L-arginine, thereby reducing the synthesis of nitric oxide and leading to the development of endothelial dysfunction and a number of cardio-vascular disorders. Arginase is a promising pharmacological target in the treatment of endothelial dysfunction and a number of cardio-vascular diseases, though the development of highly-selective arginase II inhibitors is still a difficult task
