In Vitro Effects of Cerium Vanadate (CeVO4) Derivatives on Paraoxonase (PON1) Enzyme

Abstract

Cerium vanadate (CeVO4)-based materials have attracted attention due to their diverse physicochemical and biological properties; however, their interactions with detoxification-related enzymes remain insufficiently characterized. This study evaluated the in vitro effects of alkaline earth metal-doped CeVO4 derivatives (Be, Mg, Ca, Sr, and Ba) on human serum paraoxonase-1 (PON1) paraoxonase activity. PON1 was purified from human serum by hydrophobic interaction chromatography (Sepharose 4B-L-tyrosine-1-naphthylamine), and enzymatic activity was measured spectrophotometrically using paraoxon as the substrate. Inhibitory effects were assessed across multiple concentrations, and IC50 values were determined from concentration-response curves. All derivatives exhibited concentration-dependent inhibition of PON1 activity, with IC50 values ranging from 117 to 213 & micro;M. Mg-and Ba-doped CeVO4 derivatives demonstrated the strongest inhibition at higher doping ratios, whereas Ca-doped derivatives showed reduced inhibitory potency with increasing substitution levels. These findings indicate that dopant identity and concentration significantly influence the interaction between CeVO4 derivatives and PON1. The study provides insight into metal oxide-enzyme interactions and highlights the importance of dopant-dependent effects in evaluating the biological and potential toxicological behavior of engineered vanadate-based materials.