[Glucosephosphate isomerase polymorphism in the teleost fish loach Misgurnus fossilis]

Using polyacrylamide gel disc-electrophoresis, the isoenzymic patterns of glucosephosphate isomerase (EC 5.3.1.9) in some tissues of adult loaches Misgurnus fossilis and in the unfertilized eggs, embryos and developing larvae of this species were determined. The sensitivity of the enzyme in the eggs and some tissues to inactivation at 45 degrees and to inhibition by high concentrations of fructose-6-phosphate was investigated. A comparison of the experimental data on the subunit composition of the bulk of the detected isoenzymes with literary data was carried out. A conclusion on the expression of four non-allelic glucose phosphate isomerase genes in the loach, i. e. two genes determining the structure of B-subunits and two genes determining the structure of B-subunits, was made. Besides, there were detected the alleles of both types of genes.