p-Hexosaminidase (EC 3.2.1.30) is markedly increased in human serum in liver disease, chronic alcoholism, and pregnancy. Knowledge of the clearance rate of plasma! serum #{237}3-hexosaminidase is n cessary to evaluate this increase. We studied the plasma clearance of p3-hexosaminidase isoenzymes (purified from human serum and placenta) after their infusion into rat circulation. A recently devel...

We have automated a manual test for detection of heterozygotes of Tay-Sachs disease by assay of hexosaminidase A in serum, based on pH inactivation [C/in. Chim. Acta 43, 417 (1973)]. The same manifold is used both for the total hexosaminidase and pH-inactivation (hexosaminidase B) procedures. Automation expedites mass screening of the Ashkenazi Jewish population for carriers of the TaySachs gen...

Lithium and nickel present low toxicity, but are able to cause alterations in different tissues. The toxic effects of lithium and nickel at different cellular levels were assessed using two inorganic chemical species: lithium chloride and nickel(II) chloride. Mouse neuroblastoma cell cultures (Neuro-2a) were exposed to both compounds for 24 h. The cytotoxic effects evaluated were cell prolifera...

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...

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...

The lysosomal enzyme, beta-hexosaminidase, exists as two major isoforms; HexA and HexB. HexA is an alpha beta-subunit heterodimer and HexB a beta-subunit homodimer. Both isoforms can remove nonreducing beta-N-acetyl-D-glucosamine residues, whereas HexA hydrolyzes charged substrates as G(M2) gangliosides as well. beta-Hexosaminidase is present in both human and rabbit tear fluid and is secreted ...

This study was designed to evaluate the effect of different conditions of collection, transport and storage on the quality of blood samples from normal individuals in terms of the activity of the enzymes ss-glucuronidase, total hexosaminidase, hexosaminidase A, arylsulfatase A and ss-galactosidase. The enzyme activities were not affected by the different materials used for collection (plastic s...

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...

Hexosaminidase activity was determined in cultured and uncultured amniotic fluid cells taken from seven pregnant women who had previously given birth to infants with Tay-Sachs disease. Complete deficiency of hexosaminidase A was found in one case, indicating a Tay-Sachs fetus. The diagnosis was confirmed on examination of various tissues after therapeutic abortion. Of the other six cases three ...