Purification of Angiotensin-Converting Enzyme (ACE) from Sheep Kidney and Inhibition Effect of Reduced Nicotinamide Adenine Dinucleotide (NADH) on Purified ACE Activity

Abstract

Angiotensin-converting enzyme (ACE, EC 3.4.15.1) is a significant enzyme that regulates blood pressure. ACE inhibitors are often used in the treatment of hypertension. In this work, ACE was purified and characterized in one step with affinity chromatography from sheep kidneys. ACE was 10305-fold purified and specific activity was 19,075 EU/mg protein. The molecular weight and purity of ACE were found with SDS-PAGE and observed two bands at about 60 kDa and 70 kDa on the gel. The effects of reduced nicotinamide adenine dinucleotide (NADH), an antioxidant compound, on purified ACE activity were also researched. NADH on ACE activity showed an inhibition effect. The inhibition type of NADH was determined to be non-competitive inhibition by the Lineweaver-Burk chart and IC 50 and K i values for NADH were 244.33 and 175.08 µM, respectively. These results suggest that antioxidant substances might be efficient in preventing hypertension.

Investigation of inhibition effect of folic acid (vitamin B9) on angiotensin-converting enzyme activity purified from human plasma

“…In a work by Strittmatter et al, the molecule weight with SDS-PAGE of ACE from rat lung and brain corpus striatum was determined to be 175 kDa and 165 kDa, respectively (Strittmatter et al, 1985). In our before works, the molecule weight of the ACE from sheep lungs and sheep kidneys was defined to be 70 and 60 kDa with SDS-PAGE (Aydin et al, 2021;Kiylik et al, 2022). In this study, the molecule weight and purity of the ACE from human plasma were described using SDS-PAGE, and 70 kDa and 60 kDa bands were analyzed on the gel (Figure 1).…”

“…In our previous work, NADH showed inhibitory effects on ACE in sheep kidneys. Ki and IC50 constants of NADH were designated as 175.08 µM and 244.33 µM, respectively (Kiylik et al, 2022). In another work, the IC50 constants for fosinopril, captopril, and lisinopril, which indicate an inhibitory efficacy on ACE purified from bovine lung, were designated as 1.159 μM, 0.835 nM, and 4.085 nM, respectively.…”