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)

The biosynthesis of galactosyl-beta 1,3-N-acetylglucosamine has been demonstrated using membrane preparations from pig trachea. Unlike the UDP-galactose:2-acetamido-2-deoxy-D-glucose 4 beta-galactosyltransferase, which is inhibited by high levels of N-acetylglucosamine, the UDP-galactose:N-acetylglucosamine 3 beta-galactosyltransferase shows no inhibition at 200 mM N-acetylglucosamine. About 80% of the total disaccharide synthesized at 200 mM N-acetylglucosamine was base-labile suggesting the 1,3-linkage, alpha-Lactalbumin inhibits galactose incorporation into galactosyl-beta 1,4-N-acetylglucosamine but has little or no effect on the activity of the 1,3-galactosyltransferase. Escherichia coli beta-galactosidase readily hydrolyzed the base-stable product, but not the base-labile component. The apparent 1,3-linked disaccharide was reduced with NaBH4 and was isolated by Bio-Gel P-2 column chromatography. Methylation analysis by gas chromatography/mass spectrometry showed tetramethyl galactose and a 3-substituted N-acetylglucosaminitol. Neither the beta 1,4 nor the beta 1,3 disaccharide was hydrolyzed by green coffee bean alpha-galactosidase. Both disaccharides were readily hydrolyzed by bovine testes beta-galactosidase. This is the first report on the galactosyltransferase which catalyzes the synthesis of the galactosyl-beta 1,3-N-acetylglucosamine linkage such as found in the Type I chain of human blood group substances. A tissue survey in rats showed only rat intestine to have readily detectable UDP-galactose: N-acetylglucosamine 3 beta-galactosyltransferase activity. The intestinal membrane fraction like the tracheal enzyme catalyzes the synthesis of two disaccharides as judged by base treatment, and these appear to be the beta 1,3 and beta 1,4 isomers of galactosyl-N-acetylglucosamine.
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PMID:Biosynthesis of galactosyl-beta 1,3-N-acetylglucosamine. 627 54

The immature sugar cane stalks studied contained less than 7% sucrose, and showed the activities of enzymes such as invertase, alpha-galactosidase, alpha-mannosidase, beta-N-acetylglucosaminidase, beta-glucosidase, beta-xylosidase, and beta-galactosidase. The alpha-galactosidase was highly purified by ammonium sulfate fractionation, gel filtration on a Sephadex G-100 column, ionexchange chromatography on DEAE-cellulose, and CM-cellulose columns, and heat treatment (60 degrees C, 15 min) in the presence of 0.2 m D-galactose. In polyacrylamide gel electrophoresis, the purified enzyme was homogeneous, having a molecular weight of approximately 46,000. In gelfiltration, it was approximately 47,000. The activity was optimum at pH 4.5 and at 60 degrees C. The purified enzyme hydrolyzed p-nitrophenyl-alpha-D-galactopyranoside (Km, 0.83 mM; Vmax, 25.0 mumol/mg/min), raffinose (Km, 25.9 mM; Vmax, 15.4 mumol/mg/min), and stachyose (Km, 13.0 mM; Vmax 2.7 mumol/mg/min), in addition to melibiose, guar gum, and locust bean gum. The hydrolysis of p-nitrophenyl-alpha-D-galactopyranoside was markedly inhibited by HgCl2, AgNO3, p-chloromercuribenzoate (PCMB), L-ascorbic acid, melibiose, stachyose, and D-galactose. Also the purified enzyme showed a lectin activity with trypsinized erythrocytes.
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PMID:Purification and properties of alpha-galactosidase from immature stalks of Saccharum officinarum (sugar cane). 627 79

Surface carbohydrates of Friend erythroleukemic-cells were modified by treatment with the exoglycosidases, alpha-galactosidase, beta-galactosidase, and neuraminidase without affecting cell growth and viability either in the presence of absence of 1.8% DMSO as inducer. When cells were incubated with a combination of alpha-galactosidase and neuraminidase and then induced, they showed an increased rate of differentiation as measured by the formation of benzidine-positive cells. These enzymes used singly, or beta-galactosidase treatment alone, or in combination with neuraminidase, did not change the rate of differentiation. Cell-surface labeling and electrophoretic separation of the glycoconjugates revealed that two regions of approximate molecular weights of 195,000 and 185,000 were neuraminidase-sensitive and one other of molecular weight of about 75,000 was sensitive to alpha-galactosidase. Both untreated and the combined alpha-galactosidase, neuraminidase-modified cells exhibited the same rate of uptake of carbon-14 DMSO, ruling out the possibility that the observed increased rate of differentiation was due to faster penetration of DMSO into enzyme-treated cells. On the other hand, the decrease in the rate of uptake of rubidium-86, an analogue of K+, by treated-induced cells was significantly enhanced over that observed with untreated-induced cells, suggesting that alpha-galactosidase plus neuraminidase modification of the cell surface was affecting at least one of the early events occurring in the Friend erythroleukemic cell differentiation program.
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PMID:Enzymatic modification of the surface carbohydrates of Friend erythroleukemic cells. 628 72

The beta-N-acetylhexosaminidase, beta-glucuronidase, alpha-galactosidase, beta-galactosidase and alpha-L-fucosidase activities, in six different species of molluscs, have been studied. The optimum pH was acid in all cases, in agreement with the lysosomal origin of these enzymes. They generally show several pI in their isoelectrofocusing profiles. Kinetic studies with enzymes having several activities in one protein, i.e. beta-N-acetylhexosaminidase and beta-galactosidase, have been carried out with mixed substrates in order to determine the occurrence of several active sites. The action of these enzymes on glycosidic rests containing natural substrates has been studied by enzymatic hydrolysis.
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PMID:[Glycosidases of various mollusks: general properties, kinetic studies and action on natural substrates]. 629 19

It has been suggested that high levels of urinary beta-glucuronidase may increase an individual's risk of bladder cancer by releasing free carcinogens from their inactive glucuronide conjugates in the bladder. The hypothesis derives in part from the high levels of urinary beta-glucuronidase observed in bladder cancer patients. Because most of the individual variation in levels of urinary beta-glucuronidase and other lysosomal enzymes in the normal population is genetically determined, we would expect that, if high glucuronidase levels were a predisposing factor in the disease, bladder cancer patients would transmit this trait to their progeny. We have tested this hypothesis and find that levels of urinary beta-glucuronidase and three other lysosomal enzymes, alpha-galactosidase, beta-galactosidase, and beta-hexosaminidase, are not significantly elevated in 34 progeny of bladder cancer patients compared to 34 matched controls. Additionally, 15 bladder cancer patients judged to be disease free for a median time of 5 years did not have elevated levels of urinary beta-glucuronidase when compared to a normal population of 125 individuals. Thus, the high levels of glucuronidase observed in bladder cancer patients are most likely a consequence of disease rather than a cause.
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PMID:Role of urinary beta-glucuronidase in human bladder cancer. 633 54

This study determined in a blind fashion the activity levels and thermostability properties of two lysosomal hydrolytic enzymes, acid phosphatase and alpha-mannosidase, in plasma samples from 25 cystic fibrosis (CF) patients and 25 age- and sex-matched normal controls. Mean alpha-mannosidase activity (3.2 +/- 1.0 mU/ml) and acid phosphatase activities (6.5 +/- 2.9 mU/ml) in CF patients were not significantly different from those found in normal individuals (2.8 +/- 0.7 and 7.6 +/- 3.4 mU/ml, respectively). Using stringent conditions no differences in thermostability properties of these enzymes were found between plasma from CF patients as compared to that of normal controls. When activity levels of these enzymes and of four additional hydrolytic enzymes, alpha-L-fucosidase, alpha-galactosidase, alpha-glucosidase and beta-galactosidase, were determined in submandibular saliva, no significant differences in enzyme levels between CF and age- and sex-matched controls were noted nor were thermostability differences found. Our data do not support the concept that altered properties of these enzymes are useful as markers for detection of CF homozygotes and heterozygotes, nor the hypothesis that the defect underlying this disease is a deficiency of post-translational modification of glycoproteins leading to their mis-compartmentalization and qualitative alteration.
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PMID:Plasma and submandibular saliva lysosomal enzymes in cystic fibrosis. 639 40

A 17-year-old Japanese boy was found to have ataxia, generalized angiokeratomas, skeletal deformities, visual impairment, and macular cherry-red spots, without hepatomegaly, splenomegaly, or renal failure. Laboratory examination disclosed a deficiency of beta-galactosidase as well as of neuraminidase activity in the leukocytes and fibroblasts, while alpha-galactosidase and alpha-L-fucosidase activities were normal. On electron microscopic examination, numerous cytoplasmic vacuoles containing flocculated material were found in the vascular endothelial cells, histiocytes, perineurial cells, and Schwann's cells.
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PMID:beta-Galactosidase and neuraminidase deficiency associated with angiokeratoma corporis diffusum. 643 42

Ten enzymes, all known to be glycoproteins, were examined by electrophoresis or gel isoelectric focusing in 12 different patients with primary or secondary sialidase deficiency. Aberrant electrophoretic mobilities of many of the enzymes attributable to abnormal sialylation were found in all the patients. In ten of the patients seven of the enzymes were affected. The unaffected enzymes were beta-galactosidase, alkaline phosphatase and beta-glucuronidase. In the cells from the two patients with I cell disease (mucolipidosis II) in which sialidase is one of many deficient enzymes, beta-galactosidase, alpha-galactosidase, alpha-fucosidase and alpha-mannosidase were undetectable, alkaline phosphatase showed a normal electrophoretic mobility and acid phosphatase, adenosine deaminase, alpha-glucosidase and beta-D-N-acetylhexosaminidase showed aberrant mobilities.
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PMID:Electrophoretic analysis of glycoprotein enzymes in the sialidoses and mucolipidoses. 645 53

Rat renal cortical lysosomes were isolated in 0.3 M sucrose containing 1 mM EDTA by differential centrifugation. Lysosomes were incubated in isotonic sucrose or isotonic glycine with various concentrations of endogenous and exogenous compounds at 37 degrees for 1 hr. Lysosomes were resedimented, and the N-acetyl-beta-glucosaminidase (NAG) activity was measured in the supernatant fraction and the disrupted pellet and the percentage of total NAG released was calculated. Gentamicin and its C1 and C2 components had similar potencies for inhibiting NAG release from lysosomes at low concentrations. The release of alpha-galactosidase and beta-galactosidase from lysosomes was also inhibited by streptomycin and gentamicin. Mepacrine at low concentrations stabilized lysosomes and at high concentrations disrupted lysosomes. This drug also enhanced the effect of low concentrations of gentamicin on lysosomes. Inositol hexaphosphoric acid was a potent antagonist of the effect of low concentrations of gentamicin and mepacrine on lysosomes. Rats were treated with gentamicin at doses of 40, 80 and 160 mg/kg for 1 and 3 days. NAG excretion in gentamicin-treated groups as compared to saline controls was unchanged at day 1. Only the 160 mg/kg treatment group showed a tendency toward elevated renal cortical NAG at day 1 (P less than 0.06). All treatment groups had elevated renal cortical NAG at day 3, while the 160 mg/kg group also had elevated NAG excretion. Lysine, arginine, L-canavanine and polymyxin B all affected NAG release from lysosomes in vitro. Lysine enhanced the disruptive effect of high gentamicin concentrations on lysosomes. Ferric and ferrous ions, tested over widely varied concentrations, inhibited NAG release at low concentrations while enhancing NAG release at high concentrations. We therefore conclude that the nephrotoxicity of aminoglycoside and other endogenous and exogenous renally excreted cationic compounds may be produced by their effects on lysosomes in the proximal renal tubule.
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PMID:Further studies of the response of kidney lysosomes to aminoglycosides and other cations. 663 87

This paper presents data on reactions of murine macrophages with a variety of lectins, with special focus on Griffonia simplicifolia I-B4 isolectin, the only lectin we tried that distinguishes stimulated macrophages from resident populations. Specificity of Griffonia simplicifolia I reaction with carbohydrate determinants at the cell surface is shown by (i) ability of alpha-galactosidase treatment of intact cells to abolish all lectin binding whereas beta-galactosidase has no effect on lectin binding, (ii) ability of methyl alpha-D-galactopyranoside to completely inhibit lectin binding with methyl alpha-D-galactopyranoside having no effect on lectin binding, (iii) ability of brief treatment of intact cells with trypsin to liberate a glycopeptide but reacts with G. simplicifolia I to form a precipitate that is dissolved by addition of methyl-alpha-D-galactopyranoside or alpha-galactosidase, (iv) ability of methyl alpha-D-galactopyranoside (but no other monosaccharide) to completely inhibit avid binding of macrophages to G. simplicifolia I lectin immobilized on an insoluble support, and (v) ability of immobilized lectin to separate macrophages into highly pure subpopulations of lectin-reactive and lectin-unreactive cells, as shown by examination of fluorescein-labeled lectin-treated cells with phase-contrast/fluorescence microscopy.
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PMID:Stimulated macrophages express a new glycoprotein receptor reactive with Griffonia simplicifolia I-B4 isolectin. 679 67


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