Hexosaminidase A is present in relatively low concentrations in cell-free amniotic fluids from pregnancies with Tay-Sachs fetuses. This isoenzyme was determined by an immunological procedure, radial immunodiffusion, by which hexosaminidase A can be directly and specifically detected, even in the presence of excess amounts of hexosaminidase B. No hexosaminidase A could be detected by the same pr...

Hexosaminidase P, the main isozyme of hexosaminidase in pregnancy serum, was isolated and purified 600-700-fold by a two-step purification procedure-affinity chromatography on Sepharose-bound eaminocaproyl-Nacetylglucosylamine, followed by ion-exchange chromatography on DEAE-cellulose. The purified enzyme was subjected to biochemical and immunochemical analysis. Its catalytic property, namely, ...

A method for the preparation of highly purified @-hexosaminidase isozymes A and B from human placenta is presented. The purified enzymes possess identical molecular weight and exhibit similar kinetic parameters with artificial fluorogenic substrates. Both enzymes catalyze the hydrolysis of Tay-Sachs ganglioside (Cer-Glc-Gal(NeuAc)-GalNAc) and the corresponding asialo-derivative (Cer-Glc-GalGalN...

Human liver extracts contain an activating protein which is required for hexosaminidase A-catalysed hydrolysis of the N-acetylgalactosaminyl linkage of G(M2) ganglioside [N-acetylgalactosaminyl-(N-acetylneuraminyl) galactosylglucosylceramide]. A partially purified preparation of human liver hexosaminidase A that is substantially free of G(M2) ganglioside hydrolase activity is used to assay the ...

A protein activator (GMz-activator) specific for stimulating the hydrolysis of G M ~ ganglioside (GalNAcb1 4GalC3 + 2aNeuAc]/?l-+ 4Glcb1-+ 1’Cer) by &hexosaminidase A has been purified over 1OS-fold with a high yield from human liver. The purification procedure includes the adjustment of the pH of liver extract to pH 4.3, followed by ammonium sulfate precipitation, Sephadex G-200 filtration, an...

Lysosomal enzyme activities were studied in cells derived from the following types of leukaemia: chronic myeloid, acute myeloid, acute myelomonocytic, acute monocytic, non-T, non-B cell acute lymphoblastic, T-cell acute lymphoblastic, B-cell chronic lymphocytic and T-cell chronic lymphocytic. Activities of beta-hexosaminidase and alpha-mannosidase were significantly higher in cells from acute m...

Hexosaminidase activity in prostatic tissue has been compared in 15 patients with benign prostatic hyperplasia and 15 patients with prostatic carcinoma. The ratio of enzymatic activity for the two substrates tested (p-nitrophenyl-2-acetamido-2-deoxy-beta-D-glucopyranoside and p-nitrophenyl-2-acetamido-2-deoxy-beta-D-galactopyranoside) was not significantly different in the two groups of patient...

Lysosomal enzymes require a mannose 6-phosphate recognition marker, constructed on asparagine-linked oligosaccharide chains, for targeting to lysosomes. We have identified the glycosylation sites of human beta-hexosaminidase B and have determined the influence of individual oligosaccharides on the phosphorylation, lysosomal targeting, and catalytic activity of the enzyme. The five potential gly...