Nakanishi Mamoru, Takanami Yoshikazu, Maruyama Taro, Murata Mitsuru, Motohashi Yoshiko, Nakano Satomi, Uchida Kagehiro, Maruyama Chizuko, Kyotani Shingo, Tsushima Motoo
Department of Clinical Pathology, Hyogo College of Medicine, Hyogo, Japan.
J Atheroscler Thromb. 2003;10(6):337-42. doi: 10.5551/jat.10.337.
Human serum paraoxonase (PON1) exists in 2 major polymorphic forms: Q (glutamine) or R (arginine) at codon 192. The PON1(192) activity polymorphism is substrate dependent. The PON1(Q192) isoform has a higher rate of in vitro hydrolysis of diazoxon, sarin, and soman, whereas the PON1(R192) isoform has higher activity for the hydrolysis of paraoxon and chlorpyrifos oxon. Both isoforms hydrolyze phenyl acetate at approximately the same rate. The present study described and evaluated a kinetic method of arylesterase activity determination with a modified fixed incubation method that used the oxidative coupling of phenol with 4-aminoantipyrine of phenyl acetate as the substrate. Our improved method shows that arylesterase activity is lower with the PON1(R192) isoform than with the PON1(Q192) isoform. The average activities of serum of individuals of a specific PON1(Q192) genotype showed higher arylesterase and lower paraoxonase activity than the PON1(R192) genotype. The ratio of paraoxonase/arylesterase activity showed a clear separation of all three PON1(192) genotypes with no overlap between the groups (QQ: < 5.0, QR: 5.0-11.0, RR: > 11.0). PCR has suggested that the PON1(192) phenotypes correspond to the PON1(192) genotypes. Therefore, when conducting epidemiological or mechanistic studies that examine the role of PON1 in organophosphorus or lipid metabolism, this ratio is more useful and informative than a PCR-based genotype alone.
人血清对氧磷酶（PON1）以两种主要的多态性形式存在：第192位密码子处为Q（谷氨酰胺）或R（精氨酸）。PON1（192）活性多态性依赖于底物。PON1（Q192）同工型对重氮磷、沙林和梭曼的体外水解速率较高，而PON1（R192）同工型对对氧磷和毒死蜱氧磷的水解活性较高。两种同工型对苯乙酸的水解速率大致相同。本研究描述并评估了一种测定芳基酯酶活性的动力学方法，该方法采用改良的固定孵育法，以苯乙酸为底物，利用苯酚与4-氨基安替比林的氧化偶联反应。我们改进后的方法表明，PON1（R192）同工型的芳基酯酶活性低于PON1（Q192）同工型。特定PON1（Q192）基因型个体血清的平均活性显示，其芳基酯酶活性较高，对氧磷酶活性较低，而PON1（R192）基因型则相反。对氧磷酶/芳基酯酶活性比值清晰地分离出所有三种PON1（192）基因型，各组之间无重叠（QQ：<5.0，QR：5.0 - 11.0，RR：>11.0）。聚合酶链反应（PCR）表明，PON1（192）表型与PON1（192）基因型相对应。因此，在进行研究PON1在有机磷或脂质代谢中作用的流行病学或机制研究时，该比值比单独基于PCR的基因型更有用且信息更丰富。
