Purification of human serum paraoxonase and effect of acetylsalicylic acid on paraoxonase activity

Paraoxonase was purified from human serum using sepharose-4B-L-tyrosine-1-napthylamine affinity chromatography. This enzyme was purified 1797-fold. SDS-polyacrylamide electrophoresis of the enzyme indicates a single protein staining band with an apparent Mr of 43 kDa. The kinetic properties of the purified enzyme were determined. The V-max and K-m are 231.5 mu/mg protein (EU) and 3.96 mM using substrate paraoxon respectively. The effect of acetylsalicylic acid on purified human serum paraoxonase has been investigated in vitro. The inhibition and activation effects of acetylsalicylic acid on serum paraoxonase activity were measured spectrophotometrically using paraoxon as the substrate. The phenotypic distribution of paraoxonase was determined using the dual substrate paraoxon and phenyl acetate as substrates. It was observed that acetylsalicylic acid inhibited human serum paraoxonase activity. In addition, an in vivo study was performed for acetylsalicylic acid in Sprague-Dawley rats. It was demonstrated that paraoxonase in the serum of Sprague-Dawley rat was activated, but activity in liver and heart was significantly inhibited.