Paraoxonase: A New Biochemical Marker of Oxidant-Antioxidant Status in Atherosclerosis

Abstract

The paraoxonase (PON, aryldialkyl phosphatase, E.C. 3.1.8.1), is an Ca-dependant enzyme that is synthesised in liver. It is related to HDL and has 43-45 kDa molecular weight with glycoprotein structure. PON is an hydrolase that has both arylesterase (E.C. 3.1.1.2) and paraoxonase (E.C. 3.1.8.1) activity (Baskol and Kose, 2004). The name of paraoxonase is comes from its useage of organic phosphorous paraoxanes as substrate. Enzyme catalyses the hydrolysis of organic phosphorous insecticides such as diisopropyl fluorophosphate (DEP) except parathion and catalyses the hydrolysis of nerve gases such as sarin, taurin which are in the same chemical group. Howewer, natural substrate of PON is not definite (Gulcu and Gursu, 2003).