Interaction of vanadium metal complexes with protein tyrosine phosphatase-1B enzyme along with identification of active site of enzyme by molecular modeling

Ayub Shaik^a, Vani Kondaparthy^a, Rambabu Aveli^a, M.Vijjulatha^a, S.Sree Kanth^a, Deva Das Manwal^a

Department of Chemistry, Osmania University, Hyderabad 500007, Telangana, India.

Abstract

Evidence from biochemical, genetic, and pharmacological studies strongly suggest that inhibition of Protein Tyrosine Phosphatase-1B (PTP-1B) enzyme could address both diabetes and obesity and thus making PTP-1B as an exciting target for drug development. It has been proven vanadyl compounds have an inhibitory action on PTP-1B. Owing to the importance of vanadium metal complexes in biology, we have synthesized and characterized various vanadium metal complexes using substituted acetyl acetones. The purpose of this investigation is to check the ability of these complexes to act as “inhibitors” on enzyme PTP-ases to reduce the serum glucose. Before performing inhibitory studies on PTP-1B enzyme, we thought it would be better to have studies on the interaction of these complexes with PTP-1B and to understand whether these metal complexes bind with protein (PTP-1B), if so, how strongly they bind, also to know the order of binding with different metal complexes. Fluorescence spectroscopy is used to study the interaction of the enzyme with vanadium metal complexes. The binding parameters Stern-Volmer constant (K_sv), Quenching rate constant (K_q), binding constant (K_b), No. of binding sites for the complex on the enzyme (n) are evaluated. From these results, it is concluded that various metal complexes do binds with PTP-1B enzyme. And we also evaluated the IC₅₀ values for these compounds on interaction with the enzyme as a potent inhibitor. Other supporting studies like molecular modeling were also done to support the obtained results. The order of binding constants, IC₅₀ values and results of molecular modeling concerning various vanadium complexes are in consistent with each other.

Keywords: Vanadium complex, Binding study, Type 2 diabetic mellitus, PTP-1B enzyme, Fluorometry.