Paraoxonase polymorphism in northwestern Indians.

OBJECTIVE

The aim of this study was to distinguish paraoxonase phenotypes by dual substrate method.

SUBJECTS AND METHODS

166 unrelated healthy northwestern Indian Punjabis were studied for basal paraoxonase activity (P), in presence of 1 M NaCl (salt-activated) using paraoxon as substrate and arylesterase activity (A) using phenylacetate as substrate.

RESULTS

The mean (+ SD) activity of these in population was 70.43 (+/-30.41), 103.11 (+/-42.87) nmol/min/ml plasma and 36.81 (+/- 9.87) micromol/min/ml plasma, respectively, with no significant difference in sexes. Based on the ratio of SAP activity to A activity, 3 distinct phenotypes could be determined with gene frequencies of PONA and PONB being 0.845 and 0.155, respectively. Between P and A, and SAP and A in both A and AB phenotypes, significant correlation was observed (A = r 0.34 and 0.62, p < 0.01; B = r 0.31 and 0.81, p > 0.01), suggesting that both enzymes belong to the same group.

CONCLUSIONS

Though northwestern Indian Punjabis have trimodal paraoxonase activity, the majority is either low homozygous (AA) or heterozygous (AB) type with enzyme activity lower than Europids.