The carboxylic ionophore, monensin, blocks the migration of glycoprotein-containing vesicles from the Golgi region to the plasma membrane in fibroblasts resulting in an accumulation of secretory products in the Golgi cisternae. Treatment of cultured I-cell fibroblasts with monensin (0.5,UM) decreased the abnormal excretion of f-hexosaminidase to 40% of untreated cultures within 15 min. A corres...

β-Hexosaminidase, which is generally present in the lysosome, is essential for glycoprotein metabolism in the maintenance of cell homeostasis. In mast cells (MCs), large amounts of β-hexosaminidase are present in the granules as opposed to the lysosome, and the biological role of MC β-hexosaminidase has yet to be fully elucidated. Therefore, we investigated the biological role of β-hexosaminida...

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 ...

Human hexosaminidases A and B were purified from placentae, using two stages of affinity chromatography, to a high degree of purity. Each enzyme was purified 5000-6000-fold, and isolated in 25-40% yield. Enzyme preparations appeared homogeneous in the analytical ultracentrifuge and by acrylamide gel electrophoresis. Hexosaminidase A contained 1.65 residues of sialic acid per molecule, whereas n...

Variant AB of infantile GM2 gangliosidosis is a fatal disease leading invariably to death within the first few years of life, due to the excessive storage of the glycolipids GM2 and GA2 which occurs in the nervous tissue of the patient. Unlike other variants of this hereditary disease, where a deficiency of hexosaminidase A, the ganglioside-GM2-degrading enzyme, could be demonstrated, the varia...

Tay-Sachs and Sandhoff diseases are lysosomal storage disorders that result from an inherited deficiency of beta-hexosaminidase A (alphabeta). Whereas the acute forms are associated with a total absence of hexosaminidase A and early death, the chronic adult forms exist with activity and protein levels of approximately 5%, and unaffected individuals have been found with only 10% of normal levels...

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, ...

Highly purified N-acetyl-beta-D-hexosaminidase B from normal urine and urine of a patient with mucolipidosis III was used to determine whether it has undergone any of the alterations associated with this genetic defect. Examination by sodium dodecyl sulphate/polyacrylamide gel electrophoresis showed that both the enzyme preparations contained protein components with apparent Mr values of 55 000...

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...