Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.2.1.20 (alpha-glucosidase)
4,237 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Circulating non-T lymphocytes had higher activities of 5'nucleotidase (plasma membrane), neutral alpha-glucosidase (endoplasmic reticulum) and basal leucine amino-peptidase than did T lymphocytes. Activities of catalase (peroxisomes), malate dehydrogenase (mitochondria), lactate dehydrogenase (cytosol) and N-acetyl-beta-glucosaminidase, beta-glucuronidase and acid phosphatase (lysosomes), were similar in the lymphocyte subfractions. Lymphocyte 5'nucleotidase (plasma membrane) in patients with common variable hypogammaglobulinaemia is much lower than normal. However, the decrease is less marked in X-linked hypogammaglobulinaemia, chronic lymphatic leukaemia or protein loosing enteropathy or in lymphocytes isolated from cord blood. Cells from patients with nephrotic syndrome had normal levels of 5'nucleotidase. Other plasma membrane marker enzymes (gamma-glutamyl transferase, leucine amino-peptidase) were normal in lymphocytes from patients with common variable hypogammaglobulinaemia. There is a selective reduction of mitochondrial (malate dehydrogenase) and cytosolic (lactate dehydrogenase) enzymes, with normal activities of lysosomal, peroxisomal and endoplasmic reticulum enzymes, in patients with common variable hypogammaglobulinaemia. The lymphocyte subcellular organelles in normal subjects and patients with common variable hypogammaglobulinaemia have similar properties on sucrose density gradient centrifugation. It is suggested that lymphocytes from patients with common variable hypogammaglobulinaemia show a specific enzymopathy and that this is not simply a reflection of cellular immaturity.
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PMID:Lymphocyte enzyme activities in immunodeficiency syndromes with particular reference to common variable hypogammaglobulinaemia. 630 45

The subcellular distribution of the Na+/H+ antiporter in renal proximal tubule cells was studied with differential and density gradient centrifugation. Enzyme markers for basolateral membranes [Na+/K+)-ATPase), brush border membranes (maltase), and a variety of intracellular organelles (NADPH cytochrome c reductase, thiamine pyrophosphatase, acid phosphatase, and succinate cytochrome c reductase) were simultaneously assayed in sucrose density gradients. Basolateral membranes (median rho = 1.150) were well separated from brush border membranes (median rho = 1.165) by this technique. Markers for other cellular organelles had intermediate or bimodal distributions. To determine the cellular location of the Na+/H+ antiporter, Na+-dependent collapse of preformed pH gradients was assayed in the sucrose density gradient fractions using acridine orange. Na+/H+ antiporter activity paralleled the distribution of the brush border membrane fractions; activity in the peak basolateral membrane fraction was less than 5% of that in the peak brush border fraction. To determine whether antiporter activity was potentially detectable in all cell fractions, nigericin was added to each fraction and K+/H+ exchange was assayed with acridine orange. Activity was present in all sucrose density gradient fractions. In addition, there was no alteration in Na+/H+ exchange activity measured in brush border membranes after mixing with cell sol or basolateral membranes, showing that neither inhibitors nor activators of the Na+/H+ antiporter were present in any of the cell fractions. These controls confirmed the finding that Na+/H+ antiporter activity was absent from basolateral membranes. The presence of the Na+/H+ antiporter in brush border membranes and its absence from basolateral membranes is consistent with its playing an important role in the vectorial transport of H+ from blood to tubular lumen in the renal proximal tubule.
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PMID:Asymmetric distribution of the Na+/H+ antiporter in the renal proximal tubule epithelial cell. 631 99

A conventional brush border membrane preparation, obtained by divalent cation precipitation of homogenates of rabbit renal cortex, was analyzed by countercurrent distribution in an aqueous dextran:polyethylene glycol two-phase system. The resulting fractions were assayed for the presence of the Na+/H+ antiporter and for a variety of biochemical marker enzymes. This analysis revealed four physically distinct membrane populations (A-D). Population A consisted of two subpopulations, A' and A", which were enriched an average of 49-fold in maltase; they were also highly enriched in alkaline phosphatase, leucine aminopeptidase, and Na+/H+ antiporter. On the basis of their marker contents, populations A' and A" appear to represent highly purified, functional brush border membrane vesicles. Population B was enriched twofold in NADPH-cytochrome c reductase and population C was enriched 12-fold in galactosyltransferase. Populations B and C accounted for 25% of the protein in the starting material and appear to reflect contamination of the brush border membrane preparation by subpopulations of endoplasmic reticulum and Golgi fragments. Population D was enriched in Na+/H+ antiporter, alkaline phosphatase, leucine aminopeptidase, Na-K-ATPase, and acid phosphatase but not maltase, NADPH-cytochrome c reductase, galactosyltransferase, or succinate dehydrogenase. Its identity is unclear, and it might consist of a multiplicity of populations from different origins.
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PMID:Na+/H+ antiporter in membrane populations resolved from a renal brush border vesicle preparation. 633 Nov 75

Much of the total genomic variation in eukaryotic organisms may be due to genes other than those coding the primary translation product. Allelic variation, especially as detectable by electrophoresis, in the post-translational processing of enzymes has been briefly reviewed with considerable attention given to a mouse gene (Neu-1) and its pleiotropic effects on several lysosomal hydrolases. Liver acid phosphatase, alpha-mannosidase, arylsulfatase B, and alpha-glucosidase are differentially sialylated as the result of allelic variation for a gene controlling liver neuraminidase activity. Strain SM/J has only 15-20% of the total neuraminidase activity of control strains and is almost totally deficient in the more heat labile of two components of liver activity. The locus controlling this variation (Neu-1) maps very near the D end of H-2 on chromosome 17, apparently within the S region of H-2. A homologous gene has been mapped near the MHC of the rat. The exact nature of the mouse mutant and its relationship to several human diseases characterized by neuraminidase deficiency has not been determined.
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PMID:Post-translational modification of enzymes: processing genes. 635 Feb 18

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

Synchronous cultures prepared by selection from an elutriating rotor were used to measure activity changes during the cell cycle of the following enzymes: acid phosphatase in Schizosaccharomyces pombe and Saccharomyces cerevisiae, alpha-glucosidase in S. cerevisiae and beta-galactosidase in Kluyveromyces lactis. There was no sign of step rises in activity in acid phosphatase but there were indications in S. cerevisiae of the linear pattern with rate doublings once per cycle that had been found previously in S. pombe. There was also no sign of step rises in the other two enzymes, in contrast to earlier results using different techniques. Asynchronous control cultures showed little or no perturbations after the first hour.
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PMID:Absence of step changes in activity of certain enzymes during the cell cycle of budding and fission yeasts in synchronous cultures. 641 49

In an attempt to provide additional quantitative markers of senescence in the nematode Caenorhabditis elegans, we have identified age-dependent increases in four lysosomal enzymes: acid phosphatase, beta-N-acetyl-D-glucosaminidase, beta-D-glucosidase, and alpha-D-mannosidase. These enzymes were judged to be lysosomal on the basis of their resemblance to analogous mammalian lysosomal enzymes with regard to subcellular fractionation, lectin binding, Km, molecular weights, inhibitor sensitivities, and pH optima. In nematode populations which had a median lifespan of 8.9 +/- 0.7 days and a maximum lifespan of 14-16 days, we observed the following increases in acid hydrolase activities per animal from day 3 (early adulthood) to day 10: (1) up to 2.5-fold for acid phosphatase; (2) 8-fold for beta-N-acetyl-D-glucosaminidase; (3) 9-fold for beta-D-glucosidase; and (4) 4-fold for alpha-D-mannosidase. Three forms of acid phosphatase and two forms of beta-D-glucosidase were separated by ion-exchange chromatography, but in each case only one form of the enzyme was primarily responsible for the age-dependent increase in total activity: acid phosphatase I increased 18-fold, while beta-D-glucosidase I increased 100-fold. By contrast, there were only slight age-dependent changes in choline acetyltransferase, acetylcholinesterase, or alpha-D-glucosidase activities after early adulthood. The age-dependent increases in acid phosphatase, beta-N-acetyl-D-glucosaminidase, beta-D-glucosidase, and alpha-D-mannosidase activities are sufficiently large and reproducible to be useful quantitative markers of senescence in C. elegans.
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PMID:Quantitative measures of aging in the nematode Caenorhabditis elegans: II. Lysosomal hydrolases as markers of senescence. 641

Mouse peritoneal macrophages that had been treated with a monovalent carboxylic ionophore, monensin, selectively secreted lysosomal and nonlysosomal granular enzymes into the medium. When macrophages were incubated with 1 to 10 microM monensin, the release of beta-glucuronidase, beta-hexosaminidase and beta-galactosidase was stimulated time and does dependently. Neither the beta-glucosidase nor acid phosphatase, enzymes bound to the lysosomal membranes, however, were released by monensin. Neutral alpha-glucosidase, shown recently to be localized in nonlysosomal granules of macrophages (15), was released by monensin at concentrations lower than those required for lysosomal enzyme release. Increased release of lysosomal enzymes also took place in a manner similar to that seen with monensin-treated macrophages after treatment of macrophages with weak bases, chloroquine and ammonium chloride. Neutral alpha-glucosidase, however, was not released when chloroquine was present in concentrations that stimulated the release of lysosomal enzymes. The UDP-galactosyltransferase activity of the Golgi apparatus in the macrophages markedly decreased after treatment with low concentration of monensin.
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PMID:Stimulation of the release of lysosomal and nonlysosomal granular enzymes from macrophages treated with monensin. 643 21

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

To define reproducible conditions for the homogenization of small-intestinal biopsy samples, tissue homogenization has been studied by the use of three different homogenizers. Tissue samples of increasing wet weights (0.5-10.8 mg) were homogenized in a fixed volume (1 ml) before DNA and protein were determined. The DNA to protein ratio was calculated for all wet weights and used as a measure for reproducible homogenization. The minimum tissue wet weight needed for analysis (2 mg) was determined from the values obtained for the DNA to protein ratio. Highly sensitive techniques are described in detail for the assay of brush border (maltase, lactase, sucrase, neutral alpha-glucosidase, alkaline phosphatase, gamma-glutamyl transferase, leucyl-beta-naphthylamidase), basolateral membrane (5'-nucleotidase), and mitochondrial (succinate dehydrogenase) marker enzymes and for four acid hydrolases (acid phosphatase, acid beta-D-galactosidase, N-acetyl-beta-D-glucosaminidase, acid diesterase) in human and rat jejunal mucosa. Linear kinetics have been established for all enzyme assays. The optimal dilution of tissue homogenate for the assay of the various enzymes has been determined to enable the determination of a maximum number of enzymes in each homogenate. The range of enzyme activities in samples of human and rat jejunal mucosa has been determined.
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PMID:Enzyme activities in human and rat jejunal mucosa. 667 54


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