Captopril is a reversible and competitive inhibitor of leukotriene A4 hydrolase (LTA4H; IC50 = 11μM). Captopril has been shown to be an inhibitor of angiotensin converting enzyme-1 (ACE1), but not ACE2 (IC50 = 22 nM). Captopril demonstrates noncompetitive inhibition of tyrosinase monophenolase activity and competitive inhibition of diphenolase activity. Captopril has also been shown to inhibit the formation of angiotensin II, a bioactive peptide that stimulates angiogenesis and increases microvessel density.