Inhibition Effects of Phenolic Compounds on Human Serum Paraoxonase-1 Enzyme

Metabolic processes in living organisms are closely related to the catalytic activity of enzymes. Inhibition or induction of enzymes leads to toxicities and metabolic interactions. This study aims to contribute to the growing drug design field by studying PON1-phenolic compound interactions. For this purpose, the paraoxonase-1 enzyme was purified from fresh human serum by using rapid and different chromatographic techniques. Additionally, it was investigated the inhibitory effects of some phenolic substances on the PON1 and was found that the purified enzyme had the molecular weight of 43 kDa and the specific activity of 3945.15 EU mg-1. These compounds showed potent inhibition against PON1, especially homovanillic acid exhibited a significant inhibition profile against PON1 with an IC50 value of 13.84±0.08 mM. Ki constants were 6.10±0.26 mM for homovanillic acid and 16.96±0.76 mM for phloridzin dihydrate. Homovanillic acid had competitive inhibition while the phloridzin dihydrate inhibited the PON1 as non-competitive. Also, molecular docking computations were performed by using the Glide XP mode. Glide energy of the homovanillic acid determined to be -23.95 kcal mol-1.