title: Plasma paraoxonase polymorphism: a new enzyme assay, population, family, biochemical, and linkage studies.
abstract: Plasma paraoxonase hydrolyzes paraoxon, the principal metabolite of the insecticide parathione. A genetic polymorphism for enzyme activity has been previously demonstrated. We describe a new assay based on the differential inhibition by EDTA of plasma paraoxonase from persons with the high-activity allele (PX*H) that suggests a trimodality of activity levels in population studies. The gene frequency of the low activity allele (PX*L) in 531 Seattle blood donors of European origin was .7207. Family studies were consistent with codominant autosomal inheritance of two alleles, PX*L (low) and PX*H (high), coding for products with different activity levels. Biochemical measurements of sera from presumed homozygotes for the two different alleles revealed minor physicochemical differences suggestive of a structural difference between the allelic products. No evidence for linkage of the paraoxonase locus with any of 19 polymorphic markers would be detected.
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000483:Alleles; D043303:Aryldialkylphosphatase; D002648:Child; D002675:Child, Preschool; D004492:Edetic Acid / Q000378:metabolism; D005260:Female; D005787:Gene Frequency; D006358:Hot Temperature; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007223:Infant; D007700:Kinetics; D008297:Male; D008875:Middle Aged; D010744:Phosphoric Monoester Hydrolases / Q000235:genetics* / Q000378:metabolism; D011110:Polymorphism, Genetic; D012737:Sex Factors
chemical_list: D004492:Edetic Acid; D010744:Phosphoric Monoester Hydrolases; D043303:Aryldialkylphosphatase