[Comparative studies of hexosaminidase P in the serum of pregnant females and hexosaminidase I2 in the serum of children with leukemia].

Hexosaminidase isoenzymes P from serum of pregnant women and I2 from serum of leukemic children were compared using various biochemical methods, namely, ion exchange chromatography, isoelectric focusing, and molecular weight determination by gel filtration. Isoenzyme I2 is activated by calcium, magnesium, and manganese. The molecular weight of isoenzyme I2 was 110,000 compared to 130,000 of isoenzyme P. The widely differing molecular weights exclude the so far suggested identity of both enzymes. Both isoenzyme P and isoenzyme I2 possess beta-chains, however, they differ in chain structure and glycosylation. This different structure of isoenzyme P may be one of the reasons for its increase during pregnancy due to the resulting impaired clearance by liver sinusoidal cells.