Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.2.1.23 (beta-galactosidase)
 14,648 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

3H-fucose and 14C-glucosamine labelled glycopeptides of the individual membrane proteins E1, E2 and E3 of Semliki Forest virus could be sequentially digested with alpha-neuraminidase, beta-galactosidase, N-acetyl-beta-glucosaminidase, alpha- and beta-mannosidase, N-acetyl-beta-hexosaminidase and finally with alpha-fucosidase. The degradations of the virus glycopeptides proceeded in the same way as stepwise digestions of reference glycopeptides of the lactosamine type obtained from IgG and alpha 1-acid glycoprotein. This suggests that all three membrane glycoproteins of Semliki Forest virus contained glycans with a monosaccharide sequence characteristic for lactosamine type oligosaccharides. The number of both distal and proximal N-acetyl-glucosamine residues was estimated to be usually two. According to exo- and endo-glycosidase digestions, fucose seemed to be attached to the innermost N-acetyl-glucosamine unit.
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PMID:Sequence analysis of lactosamine type glycans of individual membrane proteins of Semliki Forest virus. 54 66

The activities of 9 acid hydrolases were determined in cell-free amniotic fluid, leucocytes and cultured fibroblasts using fluorogenic substrates. The specific activities of beta-glucosidase, alpha-fucosidase, beta-hexosaminidase, and arylsulphatase A and B were found to be in the same range in cell-free amniotic fluid and in leucocyties. The isoenzyme pattern of these 5 hydrolases as well as that of acid phosphatase and alpha-mannosidase showed some similarities in all three specimens studied; the pattern of alpha- and beta-galactosidase obtained by isoelectric focusing was different in the 2 types of cells studied and in the cell-free amniotic fluid.
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PMID:Isoelectric focusing pattern of acid hydrolases in cultured fibroblasts, leucocytes and cell-free amniotic fluid. 57 95

In primary amniotic fluid cultures, four distinct types of cells were characterized as epithelioid (E I and E II), fibroblast-like (F), And large cells, Small numbers (1-200) of freeze-dried cells were isolated from colonies of each cell type and analyzed for the activity of three lysosomal enzymes: beta-N-acetylglucosaminidase, beta-galactosidase, and alpha-glucosidase. When expressed per cell, the activities for each of the enzymes were not significantly different among the small types of cells (EI, EII, and F). However, 5 to 10-fold higher enzyme activities were found in the large cells. The dry mass of individual large cells, as measured by microinterferometry, was also 5 to 10 times higher than that of the smaller cell types. When expressed per unit of dry mass, the enzyme activities tested, appeared to be independent of the type of amniotic fluid cell. The significance of this observation for the rapid prenatal diagnosis of metabolic diseases is discussed.
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PMID:Lysosomal enzyme activities in different types of amniotic fluid cells measured by microchemical methods, combined with interference microscopy. 63 47

Fibroblasts were incubated in the presence of the anti-microtubular drugs colchicine, vinblastine and vincristine. In concentrations between 10nm and 1 mM these drugs stimulated the secretion of beta-N-acetylglucosaminidase, alpha-N-acetylglucosaminidase and beta-glucuronidase, but not of beta-galactosidase. The endocytosis of beta-N-acetylhexosaminidase and alpha-N-acetylglucosaminidase, but not of beta-glucuronidase, was inhibited at drug concentrations higher than 0.1 micrometer. Formation, secretion and association with the cell membrane of sulphated proteoglycans were not affected by anti-microtubular drugs. Endocytosis of sulphated proteoglycans and their subsequent degradation was inhibited by drug concentrations above 0.1 micrometer. The inhibition of intracellular glycosaminoglycan degradation led to a moderate storage of these compounds. These results suggest that microtubules participate in the control of secretion and endocytosis of lysosomal enzymes, and in the endocytosis and degradation of lysosomal substrates such as sulphated proteoglycans.
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PMID:Studies on secretion and endocytosis of macromolecules by cultivated skin fibroblasts. Effects of anti-microtubular agents on secretion and endocytosis of lysosomal hydrolases and of sulphated glycosaminoglycans. 63 45

The effects of age-specific peculiarities and the duration of maintaining rats on a ration with 4 per cent of protein (the initial mass of rats in the 1st group 100 g each; duration of the experiment--30 days. Initial mass rats in the 2d group--200 g each; duration of experiment--90 days on the activity of the lysosomal hydrolase was studied. The latter included beta-glucosidase, beta-galactosidase, beta-glucoronidase, beta-N-acetylglucosaminidase, arylsulfatase A and B, acid phosphatase, phospholipase A1 and A2, cholinesterase, the total proteolytic activity and that of catepsines A, B, C and D. An ambiguity of changes in the enzymes activity in the animals of the 1st and 2d groups was revealed. Placing the growing animals on a ration containing 4 per cent of protein produces an activation of the most of the lysosomal enzymes, whereas in animals of the 2d test group the nature of changes in the activity of individual enzymes proved to differ quite appreciably. Thus, the summary activity of catepsines, beta-glucoronidase and cholinesterase was below the control level, while the activity of beta-galactosidase, beta-N-acetyl-glucoseaminidase and phospholipase A1 and A2 went up. A prolonged maintenance of rats on a protein-poor ration led to upsetting the stability of the lysosomal membranes, which manifested itself in a higher solubilization of lysosomal enzymes in vitro.
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PMID:[Characteristics of the enzymatic adaptation of rat liver lysosomes to protein deficiency]. 68 19

The involvement of glycoconjugates in the insulin-receptor interactions in mouse liver is tested by digestions of membranes with various enzymes. Trypsin decreased the binding of [125I]insulin to liver membranes. After digestion with beta-galactosidase no ""high affinity'' receptor sites could be detected. The effects observed with plant lectins confirm the involvement of galactoconjugates in the insulin binding process. Sophora japonica and Ricinus communis lectins (with galactose specificity) and concanavalin A largely inhibit the binding process of insulin and those effects concern the ""high affinity'' receptor sites. Other lectins (wheat germ agglutinin, Dolichos) and enzymes (alpha-L-fucosidase, beta-N-acetyl-hexosaminidase and neuraminidase) are without effect on insulin binding. Comparative studies performed on diabetic mouse liver membrane (KK mice), previously characterized by decreased number of insulin receptors, are in good agreement with qualitatively similar receptor sites in both non-diabetic (control) and diabetic mice. Effects of enzymes and lectins yielded same results as compared to control membranes. Plasma membrane proteins and glycoproteins in both types of mouse are indistinguishable with respect to enzymic and chemical analysis. Sodium dodecyl sulphate acrylamide gel electrophoresis shows identical patterns. Moreover, the decrease in the number of insulin receptors is easily reversed with diet restriction. These data are consistent with the similarity of receptor sites in control and diabetic liver membrane.
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PMID:Involvement of glycoconjugates in insulin-receptor interactions. Studies in liver plasma membranes of control and diabetic mice. 69 17

The pH optima and apparent Km and Vmax values were determined for nine glycosidases of the retinal pigment epithelium (RPE) of the calf. In terms of micromoles of substrate cleaved per milligram protein per hour, the following relative order of enzymatic activities was observed: beta-N-acetylglucosaminidase greater than alpha-glucosidase = beta-N-acetylgalactosaminidase greater than alpha-mannosidase greater than beta-galactosidase greater than beta-glucosidase greater than alpha-fucosidase greater than alpha-galactosidase greater than beta-glucuronidase. The pH optimum of each of these enzymes was in the acidic range (below pH 6). All these findings refer to enzymatic activities of bovine RPE preparations obtained by the brushing procedure of Glocklin and Potts and washing as described by Berman and Feeney. Thus they may relate to those activities associated with particulate components of the RPE cell and not to the more soluble glycosidases. The distribution of the glycosidases between the washes of the cells and the final pellet of bovine RPE cells was examined. The activities of 10 glycosidases in the RPE of the embryonic chick were also examined. Neither beta-mannosidase nor beta-fucosidase activities could be detected in washed bovine RPE cells, although beta-mannosidase was detected in RPE of the embryonic chick. The presence of isoenzymes of beta-glucuronidase in bovine RPE was indicated. Specificity by beta-glucuronidase of bovine RPE for synthetic substrates was observed.
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PMID:Glycosidases of the retinal pigment epithelium. 70 Sep 67

The origin and properties of cytosolic neuraminidase (acylneuraminyl hydrolase, EC 3.2.1.18) from pig brain were studied. 1. The brain extracts containing the cytosol derived from neuronal bodies and glial cells carry 0.69 munits neuraminidase/g fresh tissue. The behaviour of neuraminidase during extraction closely paralleled that of authentic cytosolic enzyme, lactate dehydrogenase; whereas, it differed from that of the lysosomal enzymes, beta-hexosaminidase and beta-galactosidase, also found in the extracts. 2. Nerve endings from either crude or purified preparations, when treated by hypoosmotic shock, released neuraminidase activity up to a maximum of 1.25 munits/g fresh tissue. The behaviour of releasable neuraminidase was always identical to that of lactate dehydrogenase and very similar to that of ATPase and acetylcholinesterase. Typical lysosomal enzymes, however, such as beta-galactosidase and beta-hexosaminidase, behaved differently under the same conditions. This neuraminidase activity is thought to be derived from the cytosol of nerve endings. 3. The specific activity of neuraminidase in nerve-ending cytosol is 15--20 times that in neuronal body and glial cell cytosol. Some properties (pH, Km value, V/t relationship) of the cytosolic enzymes of different origin are similar; others (stability on standing at 4 degrees C; resistance to freezing and thawing) are different. Hypoionic solutions caused both cytosolic neuraminidases to slowly precipitate and to assume a stable insoluble form which was still active.
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PMID:Studies on brain cytosol neuraminidase. II. Extractability, solubility and intraneuronal distribution of the enzyme in pig brain. 71 57

Tetrahymena were grown in proteose-peptone medium supplemented with glucose, mannose, fructose, galactose, acetate, succinate, or pyruvate and then washed and resuspended in a non-nutrient salt solution and the amounts of 7 acid hydrolases secreted into the medium in a one hour incubation were measured. Cells that had been grown in the presence of glucose secreted about half the amounts of acid phosphatase, beta-N-acetylglucosaminidase and acid protease as did control cells grown in unsupplemented medium. Pyruvate was about as effective as glucose and both were slightly more effective than acetate or fructose. Succinate had little effect. Similar experiments showed that alpha-mannosidase, beta-fucosidase, and beta-galactosidase are secreted into the salt solution and the secretion is reduced by prior growth of the cells in medium supplemented with glucose or mannose but not galactose. Except for alpha-mannosidase, these reductions in amounts of hydrolase secreted were not accompanied by appreciable changes in intracellular activity, and therefore demonstrate a persistent effect of growth in the presence of certain metabolites on the subsequent secretion of lysosomal hydrolases. Since the inhibition of subsequent secretion depended on both the individual metabolite and the particular hydrolase examined, it appears that the effect of metabolites is not limited to a general inhibition of secretion but may differentially alter some properties of lysosomal subpopulations. A preliminary characterization of the secreted acid protease of Tetrahymena suggests that there may be two acid proteases released, since up to 25% of the activity was not inhibited by high concentrations of pepstatin, leupeptin, or chymostatin.
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PMID:Effects of metabolites present during growth of Tetrahymena pyriformis on the subsequent secretion of lysosomal hydrolases. 80 52

An activator stimulating the enzymic hydrolysis of sphingoglycolipids has been purified from human liver. The purity of the activator, as examined by disc gel electrophoresis, showed one major band stained with both amido black and periodate-Schiff reagent. Chemical analyses identify the activator as a glycoprotein. The physical properties of the activator are: heat-stable, nondialyzable; molecular weight, about 21,000; isoelectric point (pI), 4.1. The purified activator stimulates the hydrolysis of GM1 by beta-galactosidase, GM2 by beta-hexosaminidase, as well as ceramide trihexoside by alpha-galactosidase A or B. The hydrolysis by glycosidases depends upon the amount of activator added. An antibody against the activator was developed from rabbits. The specificity of the antibody to the activator has been established. The antibody was used to make the affinity column for isolation of the activator. It was also used to develop a sensitive immunodiffusion method to detect the activator.
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PMID:An activator stimulating the enzymic hydrolysis of sphingoglycolipids. 81 23


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