Prorenin is the inactive precursor of renin, which is a key enzyme in the regulation of blood pressure and electrolyte balance. In renal juxtaglomerular cells, sequential cleavage of the N-terminal 20 and 46 amino acids of preprorenin produces prorenin and active renin, respectively. Renin catalyzes the conversion of angiotensinogen to angiotensin I. Prorenin exhibits 5-10% of the proteolytic activity of renin, however, the blood circulating levels are 10 times higher.