Investigation of in vitro effects of NADH and FAD compounds on the activity of angiotensin converting enzyme (ACE, E.C.3.4.15.1) purified from sheep kidney by affinity chromatography method

The angiotensin converting enzyme (ACE EC 3.4.15.1) plays a central role in regulating blood pressure by producing vasoconstrictor angiotensin II. In this study, ACE was purified from sheep kidney by affinity chromatography in one step and the purification rate of enzyme was 10305 fold and specific activity was calculated as 19075 EU/mg protein. The SDS-PAGE showed that ACE had two subunits with a molecular weight of 60 kDa and 70 kDa. The effect of NADH and FAD compounds on ACE activity purified from sheep kidney was investigated. The FAD compound showed no effect on ACE activity. NADH compound showed inhibition effect. For the NADH compound, % Activity against inhibitor concentration was plotted. The IC50 value of this graph was calculated as 244.33 µM. Lineveawer-Burk graph was used to determine the type of inhibition and Ki value. Inhibition type was determined as non-competitive inhibition and Ki value175.08 µM.