background: glycosidases profusion in male reproductive fluids suggests a possible relationship with sperm function. although hexosaminidase (hex) is the most active glycosidase in epididymal fluid and seminal plasma, as well as in spermatozoa, glucosidase is considered a marker for epididymal function and azoospermia. objective: the aim of this study was to determine hex activity in seminal pl...

We recently presented data showing that mannose-6-phosphate was a potent competitive inhibitor of pinocytosis of human platelet beta-glucuronidase, and that treatment of "high-uptake" forms of the enzyme with alkaline phosphatase destroyed the high-uptake property of the enzyme without diminishing its catalytic activity. These data indicate that phosphate is a necessary component of the recogni...

Tay-Sachs disease (TSD, GM2 gangliosidosis, Type I) is an autosomal recessive lysosomal storage disease caused by deficiency of beta-hexosaminidase A (Hex A) resulting from mutations in the gene (HEXA) encoding the alpha-subunit of the enzyme. Three mutations, in exons 7 and 11 and at the exon 12-intron 12 junction, account for > 90% of alleles identified in obligate Ashkenazi Jewish carriers. ...

The two major isozymes of N-acetylhexosaminidase, namely hexosaminidases A and B were quantitatively determined in tissues and biological fluids of both normal individuals and Tay-Sachs patients. The determination was carried out by two sensitive immunoassays:radial immunodiffusion, using chromogenic substrate, and radioimmunoassay, which were developed in this study. For this purpose [correcte...

Sulfate transport was examined in rat liver lysosomes that were isolated from thyroid hormone-treated, thyroidectomized, and control animals. Sulfate uptake was significantly decreased in lysosomes from animals that had received intraperitoneal T3 (3,5,3'-triiodothyronine) at a dose of 20 micrograms/100 g body weight. The effect of T3 was maximal by 24 h post-injection and resulted in marked de...

Rab27a activity is affected in several mouse models of human disease including Griscelli (ashen mice) and Hermansky-Pudlak (gunmetal mice) syndromes. A loss of function mutation occurs in the Rab27a gene in ashen (ash), whereas in gunmetal (gm) Rab27a dysfunction is secondary to a mutation in the alpha subunit of Rab geranylgeranyl transferase, an enzyme required for prenylation and activation ...

The severe neurodegenerative disorder, Tays-Sachs disease, is caused by a beta-hexosaminidase alpha-subunit deficiency which prevents the formation of lysosomal heterodimeric alpha-beta enzyme, hexosaminidase A (HexA). No treatment is available for this fatal disease; however, gene therapy could represent a therapeutic approach. We previously have constructed and characterized, in vitro, adenov...

This study aimed to evaluate the anti-allergic potential of Echium plantagineum L. bee pollen and to characterize its primary metabolites. The activity of E. plantagineum hydromethanolic extract, devoid of alkaloids, was tested against β-hexosaminidase release in rat basophilic leukemic cells (RBL-2H3). Two different stimuli were used: calcium ionophore A23187 and IgE/antigen. Lipoxygenase inhi...

An Ashkenazi Jewish brother and sister developed progressive ataxia and proximal neurogenic muscle weakness, associated with supranuclear ophthalmoplegia, in the fourth decade of life. Hexosaminidase A activity, assayed using both synthetic and natural substrates, was severely reduced in the patients' plasma, leukocytes, and skin fibroblasts. Enzyme activity in their parents was in a similar ra...