The human serum paraoxonase/arylesterase gene (PON1) is one member of a multigene family.
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.
Primo-Parmo
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SL
Department of Anesthesiology, University of Michigan Medical School, R5036 Kresge II Building, Ann Arbor, Michigan, 48109-0572, USA.
Sorenson
R C
RC
Teiber
J
J
La Du
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BN
D000595:Amino Acid Sequence; D000818:Animals; D043303:Aryldialkylphosphatase; D001483:Base Sequence; D002645:Chickens; D002874:Chromosome Mapping; D002897:Chromosomes, Human, Pair 7; D004247:DNA / Q000097:blood; D017931:DNA Primers; D004285:Dogs; D004950:Esterases / Q000097:blood* / Q000235:genetics*; D005091:Exons; D015723:Gene Library; D006801:Humans; D007438:Introns; D007527:Isoenzymes / Q000097:blood / Q000235:genetics; D007962:Leukocytes / Q000201:enzymology; D008099:Liver / Q000201:enzymology; D051379:Mice; D008807:Mice, Inbred BALB C; D008969:Molecular Sequence Data; D005810:Multigene Family; D009115:Muridae; D016133:Polymerase Chain Reaction; D011817:Rabbits; D017384:Sequence Deletion; D017386:Sequence Homology, Amino Acid; D014422:Turkeys
D017931:DNA Primers; D007527:Isoenzymes; D004247:DNA; D004950:Esterases; D043303:Aryldialkylphosphatase; C468406:PON1 protein, human; C468411:PON2 protein, human; C113656:PON3 protein, human