Primo-Parmo S L, Sorenson R C, Teiber J, La Du B N
Department of Anesthesiology, University of Michigan Medical School, R5036 Kresge II Building, Ann Arbor, Michigan, 48109-0572, USA.
Genomics. 1996 May 1;33(3):498-507. doi: 10.1006/geno.1996.0225.
A physiological role for paraoxonase (PON1) is still uncertain, but it catalyzes the hydrolysis of toxic organophosphates. Evidence that the human genome contains two PON1-like genes, designated PON2 and PON3, is presented here. Human PON1 and PON2 each have nine exons, and the exon/intron junctions occur at equivalent positions. PON1 and PON2 genes are both on chromosome 7 in human and on chromosome 6 in the mouse. Turkey and chicken, like most birds, lack paraoxonase activity and are very susceptible to organophosphates. However, they have a PON-like gene with approximately 70% identity with human PON1, PON2, and PON3. Another unexpected finding is that the deduced amino acid sequences of PON2 in human, mouse, dog, turkey, and chicken and of human PON3 are all missing the amino acid residue 105, which is lysine in human PON1. The expanded number of PON genes will have important implications for future experiments designed to discover the individual functions, catalytic properties, and physiological roles of the paraoxonases.
对氧磷酶（PON1）的生理作用仍不确定，但它能催化有毒有机磷酸酯的水解。本文提供了证据表明人类基因组包含两个类对氧磷酶基因，分别命名为PON2和PON3。人类的PON1和PON2各有9个外显子，且外显子/内含子连接点位于相同位置。PON1和PON2基因在人类中都位于7号染色体上，在小鼠中位于6号染色体上。火鸡和鸡与大多数鸟类一样，缺乏对氧磷酶活性，对有机磷酸酯非常敏感。然而，它们有一个与人类PON1、PON2和PON3具有约70%同源性的类PON基因。另一个意外发现是，人类、小鼠、狗、火鸡和鸡的PON2以及人类PON3的推导氨基酸序列都缺失了第105位氨基酸残基，而该残基在人类PON1中是赖氨酸。对氧磷酶基因数量的增加将对未来旨在发现对氧磷酶的个体功能、催化特性和生理作用的实验产生重要影响。
