A sandwich enzyme-linked immunosorbent assay for human serum paraoxonase concentration

Serum paraoxonase (PON) is associated with plasma high density lipoproteins , and prevents the oxidative modification of low density lipoproteins. We h ave developed a sensitive sandwich enzyme-linked immunosorbent assay (ELISA ), using two monoclonal antibodies against PON, to measure serum PON concen tration, The concentration of PON in healthy Japanese subjects was 59.3 +/- 1.3 mu g/mL (mean +/- SEM; n = 87), Serum PON concentrations in relation t o the PON 192 genetic polymorphism were: 69.5 +/- 2.9 mu g/mL in the QQ gen otype; 63.0 +/- 1.9 mu g/mL in the QR genotype; and 52.8 +/- 1.7 mu g/mL in the RR genotype, Concentrations were significantly lower in the RR than in the QQ genotype (P < 0.01). Serum paraoxonase specific activity was higher in RR than in QQ subjects (18.6 +/- 0. 40 vs. 2.56 +/- 0.05 nmol/min/mu g, P < 0.01), but arylesterase specific activity was unrelated to genotype, P ON concentration was positively associated (P < 0.001) with both serum aryl esterase activity and, after adjusting for the effect of the position 192 p olymorphism, with serum paraoxonase activity. Subjects with angiographicall y verified coronary heart disease had significantly lower PON concentration s than the healthy controls (52.0 +/- 2.3 mu g/mL; n = 35, P < 0,01), This association was independent of the position 192 genotype.jlr Our new ELISA should be of value for epidemiologic and clinical studies of serum PON conc entration.