ABSTRACT

Paraoxonase-1 (PON1) is an HDL-associated enzyme implicated in the pathogenesis of atherosclerosis by protecting lipoproteins against peroxidation. PON1 has two genetic polymorphisms both due to amino acid substitution, one involving glutamine and arginine at position 192 and the other leucineand methionine at position 55. Our study aimed to compare the effect of PON192 polymorphism and PON1 activity in patients with type 2 diabetes mellitus (T2DM) and non-diabetic controls

50 patients with T2DM and 30 non-diabetic controls were included in this study. The PON192 polymorphism was studied by polymerase chain reaction/restriction fragment length polymorphism (PCR/RFLP). Paraoxonase activity was measured by spectrophotometric method

The frequencies of the QQ, QR and RR genotypes were found as 36.5 and 14% in type 2 diabetes patients and 26.67, 46.66, 26.67% in control subjects, respectively. The paraoxonase activity was detected at lower levels in diabetics (102.0 ±38.9) than in control subjects (158.1±63.7). PON1192 RR homozygotes had significantly higher PON activity than QR and QQ genotypes among control and type 2 diabetes patients (p<0.005)

In comparing the activities of three genotypes of the control and type 2 diabetic groups; all activities were found significantly lower in diabetics. In conclusion, we suggested that paraoxonase activities are affected by PON1 genetic variability in patients with type 2 diabetes mellitus and controls.