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)

Intracellular transport of two lysosomal enzymes, acid alpha-glucosidase and beta-hexosaminidase, was analyzed in human fibroblasts. The precursors of beta-hexosaminidase in normal fibroblasts were released from the membrane fraction by treatment with mannose 6-phosphate, but the precursor of alpha-glucosidase was not. Percoll density gradient centrifugation revealed a normal amount of acid alpha-glucosidase activity in heavy lysosomes in I-cell disease fibroblasts despite impaired maturation and defective phosphorylation, and beta-hexosaminidase activity was markedly reduced in lysosomes. It was concluded that the membrane-bound precursor of acid alpha-glucosidase is transported to lysosomes by a phosphomannosyl receptor-independent system although the enzyme lacks the recognition marker for the phosphomannosyl receptor and processing of an intermediate form to mature forms does not occur in this disease.
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PMID:Intracellular transport of acid alpha-glucosidase in human fibroblasts: evidence for involvement of phosphomannosyl receptor-independent system. 284 24

Immunogold double-labeling and ultrathin cryosections were used to compare the subcellular distribution of albumin, mannose 6-phosphate receptor (MPR), galactosyltransferase, and the lysosomal enzymes cathepsin D, beta-hexosaminidase, and alpha-glucosidase in Hep G2 cells. MPR and lysosomal enzymes were found throughout the stack of Golgi cisternae and in a trans-Golgi reticulum (TGR) of smooth-surfaced tubules with coated buds and vesicles. The trans-Golgi orientation of TGR was ascertained by the co-localization with galactosyltransferase. MPR was particularly abundant in TGR and CURL, the compartment of uncoupling receptors and ligands. Both TGR and CURL also contained lysosomal enzymes, but endogenous albumin was detected in TGR only. The coated buds on TGR tubules contained MPR, lysosomal enzymes, as well as albumin. MPR and lysosomal enzymes were also found in coated pits of the plasma membrane. CURL tubules seemed to give rise to smooth vesicles, often of the multivesicular body type. In CURL, the enzymes were found in the lumina of the smooth vesicles while MPR prevailed in the tubules. These observations suggest a role of CURL in transport of lysosomal enzymes to lysosomes. When the cells were treated with the lysosomotropic amine primaquine, binding of anti-MPR to the cells in culture was reduced by half. Immunocytochemistry showed that MPR accumulated in TGR, especially in coated buds. Since these buds contain endogenous albumin and lysosomal enzymes also, these data suggest that coated vesicles originating from TGR provide for a secretory route in Hep G2 cells and that this pathway is followed by the MPR system as well.
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PMID:Possible pathways for lysosomal enzyme delivery. 293 16

As shown in studies of 123 patients with various nephropathies, activities of alpha-glucosidase and N-acetyl-beta-D-hexosaminidase in urine of the patients correlated with severity and stages of these diseases; at the same time, simultaneous estimation of both enzymatic activities in urine was shown to be more informative in diagnostic of kidney impairments. Low values of correlation coefficient (r = 0.35 +/- 0.09) between daily excretion of protein and the activity of neutral alpha-glucosidase in urine showed that the enzyme activity did not depend on proteinuria and was independent test for kidney impairment. Estimation of alpha-glucosidase activity could be used for control of the therapy; the enzymatic activity in urine correlated distinctly with the clinico-laboratory patterns of the patients studied.
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PMID:[Diagnostic value of determining neutral alpha-glucosidase and N-acetyl-beta-D-hexosaminidase activity in the urine in kidney pathology]. 294 5

Various lysosomal acid hydrolases from tissues of Niemann-Pick mice, a mutant strain of C57BL/KsJ mice (spm/spm), were examined and compared to those from control mice. Activities of beta-hexosaminidase, beta-galactosidase, acid phosphatase, and cathepsin L were elevated in the liver and spleen of the affected mice, whereas no significant changes in beta-glucosidase and acid alpha-glucosidase were observed. Alpha-Mannosidase and neutral alpha-glucosidase activities were rather decreased in the affected mouse liver. The level of beta-hexosaminidase in the Niemann-Pick mice was raised sixfold in the liver and two- to threefold in the spleen and brain, whereas its total activity was decreased in the kidney. Sixty to ninety percent of total activity of lysosomal hydrolases was solubilized with 0.1% Triton X-100 in control mice, but most of the beta-hexosaminidase activity of the Niemann-Pick mice remained associated with the membrane fraction of liver lysosomes. The beta-hexosaminidase of the Niemann-Pick mice was appreciably stable when heated at 55 degrees C, while hydrolases of the affected mice and all of the enzymes tested in control mice were heat labile. The relative content of two beta-hexosaminidase fractions separated by DEAE-cellulose column chromatography was 8% for beta-hexosaminidase I and 92% for beta-hexosaminidase II in the case of the control mouse liver. The isozyme pattern of hexosaminidases in Niemann-Pick mice was similar to that of control enzymes. However, the beta-hexosaminidase II accumulated in Niemann-Pick mouse liver was different from that of the control in optimum pH, Km values and thermostability.
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PMID:Properties of lysosomal beta-hexosaminidase accumulated in Niemann-Pick mouse liver. 294 29

A number of lysosomal enzymes are secreted from Tetrahymena pyriformis during growth and during starvation. The secretion is energy-dependent and kinetically different among hydrolases. On the basis of the secretion kinetics under starvation conditions, Tetrahymena hydrolases can be separated into three classes. The first group containing acid phosphatase, beta-glucosidase and alpha-galactosidase, are secreted slowly. Within this group about 4% of the initial cellular activity is released per hour. The second group of enzymes, including alpha-glucosidase, alpha-mannosidase and beta-galactosidase, exhibit moderate secretion (11-15% of the initial cellular activity per hour). The third group, N-acetyl-beta-hexosaminidase, has the highest rate of secretion (22% of the initial cellular activity per hour). N-Acetyl-beta-hexosaminidase shows a continuous increase in overall activity during starvation, which is completely blocked by adding cycloheximide; its secretion is also suppressed. Such involvement of enzyme biosynthesis was not seen in the first and second groups. Furthermore, treatment with weak bases caused inhibited secretion of differing degree among acid phosphatase (group I), alpha-glucosidase (group II) and N-acetyl-beta-hexosaminidase (group III).
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PMID:Secretion heterogeneity of lysosomal enzymes in Tetrahymena pyriformis. 295 37

Mesenteric vascular occlusion and intestinal obstruction are difficult-to-diagnose medical emergencies. We evaluated a large panel of biochemical markers as diagnostic and prognostic indicators in a rat model of intestinal infarction and partial, complete, and strangulated intestinal obstruction. After intestinal infarction and obstruction, laboratory data are distinctly abnormal. Serum urea nitrogen dramatically increased in all groups, but most rapidly in the groups with infarction and strangulated obstruction. Inorganic phosphorus proved to be a sensitive indicator of infarction, but less so for any form of obstruction. While all members in the infarct group demonstrated significant increases in the aminotransferases, creatine kinase, and alkaline phosphatase, such increases in the groups with obstruction were less pronounced. Serum maltase assays revealed decreasing activities in all members of the groups with complete and strangulated obstruction, but in only 17% of the rats with partial obstruction. Serum maltase activity increased from abnormally low values after surgery to abnormally high values in the six animals that recovered from partial intestinal obstruction. The proportion of hexosaminidase A (of total beta-N-acetylhexosaminidase, EC 3.2.1.30) was generally abnormal in rats with complete and strangulated obstruction.
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PMID:Acute intestinal infarction or obstruction: search for better laboratory tests in an animal model. 296 10

The epidermal growth factor receptor in cells of the UMR 106-06 clonal osteoblast line has been shown to be structurally similar to that previously characterized in other cell lines. A specific receptor component of approximately 165,000-185,000 Mr has been identified by polyacrylamide gel electrophoresis using the chemical crosslinker disuccinimidyl suberate to crosslink 125I-EGF to its receptor. Tunicamycin treatment of cells resulted in a dose-dependent loss of binding suggesting involvement of glycosyl moieties in EGF binding to its receptor. Competitive binding studies carried out using wheat germ lectin (WGL), concanavalin A (CON.A.), soybean lectin (SBL), and lentil lectin (ILL) to compete for binding of 125I-EGF revealed that CON A, WGL, and to a lesser extent LL could inhibit EGF binding; SBL was without effect. Treatment of the cells with neuraminidase which cleaves terminal sialic acid residues resulted in total loss of binding while alpha-glucosidase, beta-N-acetylglucosaminidase and alpha-mannosidase were without effect. These data indicate a specific interaction of EGF with terminal sialic acid residues of the EGF receptor. However, it would seem that the mannose residues which appeared to modify EGF binding were not available for the action of the above enzymes due to the presence of sialic acid.
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PMID:Molecular characterization of the EGF receptor and involvement of glycosyl moieties in the binding of EGF to its receptor on a clonal osteosarcoma cell line, UMR 106-06. 300 87

Activities of five acid glycosidases were examined in leukocytes of 30 healthy persons, 17 patients with chronic myeloid leukemia (CML) and 7 patients with acute myeloid leukemia (AML). In leukocytes of the patients with CML activities of alpha-D-mannosidase, N-acetyl-beta-D-hexosaminidase and beta-D-glucurodase were significantly higher (p less than 0.01) and those of alpha-D-galactosidase and alpha-D-glucosidase were somewhat higher (p less than 0.05) as compared with control leukocytes. Activities of all five glycosidases in leukocytes of patients with AML were within the normal limits. Glycosidase activities were also examined in leukocytes of three groups of patients with CML at different stages of the disease: chronic, progressive and blast crisis. All the enrymes exhibited the highest activity in the first group of patients; the activities of these enxymes in the second group were lower and those in the third group were close to normal. When CML leukocytes were fractionated using the Ficoll-verografin method, the activities of the enzymes in the interface fraction (unmatured cells) were higher than those in the bottom fraction (matured granulyocytes). These data suggest that the increased glycosidase activity in CML cells is due to the presence of the population of unmatured granulocytes which are distinct from blast cells.
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PMID:[Acid glycosidases in leukocytes of patients with chronic and acute myeloid leukemias]. 301 May 66

Activities of 10 lysosomal hydrolase enzymes (beta-hexosaminidase, beta-galactosidase, alpha-galactosidase, alpha-mannosidase, beta-mannosidase, alpha-L-fucosidase, beta-glucuronidase, alpha-glucosidase, alpha-N-acetylgalactosaminidase, and acid phosphatase) were determined in eight organs (brain, liver, kidney, spleen, heart, skeletal muscle, lung, and testis) in males and females of six inbred mouse strains (C57BL/6J, C3H/HeJ, DBA/2J, BALB/cJ, P/J, and 129/J). Examples of enzyme-specific variation, organ-specific variation, and enzyme- and organ-specific variation were found. New enzyme-specific variants with the features of systemic regulators for alpha-L-fucosidase and beta-mannosidase were found. Known variants were detected. Organ-specific variants had some of the properties expected for a new class of genes affecting multiple enzymes: organ-specific regulators.
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PMID:Variation in ten lysosomal hydrolase enzyme activities in inbred mouse strains. 302 5

Cultured skin fibroblasts derived from patients with cystic fibrosis contain 2.1-fold more acid alpha-glucosidase (EC 3.2.1.3) than normal fibroblasts. This difference is amplified to 2.3-fold when the cells are extracted in Triton X-100. In a study of 14 fibroblast cell lines derived from CF homozygotes and heterozygotes, normal individuals and patients with other recessively inherited disorders, normal individuals could be distinguished from either CF homozygotes or heterozygotes based on the ratio of acid alpha-glucosidase to beta-hexosaminidase when fibroblasts were extracted in either water or Triton X-100. However, the best distinction could be made with water extracts as there was no overlap among individual data points in the three categories. The acid to neural alpha-glucosidase ratio only distinguished CF homozygotes from normal individuals when cells were extracted in Triton X-100. The use of a ratio relationship of acid alpha-glucosidase with beta-hexosaminidase allows the comparison of data from multiple experiments on different days of assay and on cells at different passage numbers. These results suggest that alpha glucosidase may have a role in the primary defect in cystic fibrosis.
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PMID:Alterations in specific activity of lysosomal alpha-glucosidase in cystic fibrosis. 307 37


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