A rapid and simple microfractionation method for the analysis of hexosaminidase A and B activities in small numbers of cultured (amniotic fluid) cells.

A simple and rapid microfractionation procedure is described which enables the separate analysis of hexosaminidase A and B activities in as little as a few hundred to a thousand cultured human cells. 25 microliter cell homogenate is added to a pellet of DEAE-cellulose and 50 microliter 0.1 M NaCl in buffer. After centrifugation the hex B and I forms are measured in the supernatant, whereas hex A is determined by direct incubation of the DEAE pellet with methylumbelliferyl substrate. The reliability and reproducibility of the method is compared with that of heat inactivation and column chromatography. The application of the procedure is illustrated by analyses of fibroblasts and cultured amniotic fluid cells from pregnancies at risk for Tay-Sachs disease and by serum assays for the diagnosis and heterozygote testing of this disease.