In silico binding affinity study of lisinopril and captopril to I/D intron 16 variant of angiotensin converting enzyme protein

ACE gene polymorphism is thought responsible to the difference of response to ACE inhibitor therapy in hypertensive patients. The inhibitory potency of ACE inhibitors are mainly determined by differences in the binding affinity. This study was conducted to investigate the inhibitory potency of lisinopril and captopril by analyzing the binding affinity of ACE protein to lisinopril and captopril in silico. Binding affinity was obtained from molecular docking using AutodockVina. Docking calculation showed lisinopril has the higher binding affinity to the C-domain than N-domain ACE, means that lisinopril was found to be more effective to inhibit D variant of ACE protein activity. In case of captopril, captopril showed the same binding affinity of captopril in both N- and C-domain (-6.1 kcal/mol). This result implied that captopril could bind to I and D variant of ACE protein with the same affinity. In conclusion, lisinopril and captopril apparently showed a difference inhibitory potency between I and D variant of ACE, as proven by calculated binding affinity.