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

We examined the effect of 45 degrees C hyperthermia on the following glycosidases in CHO cells: beta-galactosidase, beta-hexosaminidase, beta-glucuronidase and alpha-mannosidase. Among these, lysosomal alpha-mannosidase exhibited the most dramatic response to hyperthermia with an increase in activity immediately after 45 degrees C hyperthermia. The increase was linearly dose-dependent with a doubling of activity for every 20 min at 45 degrees C. In contrast to alpha-mannosidase, beta-glucuronidase, beta-galactosidase, and beta-hexosaminidase showed only minor alterations in activity, or none, after hyperthermia of 10 to 60 min at 45 degrees C. Induction of thermotolerance enhanced the heat resistance of beta-galactosidase, but caused increased heat sensitivity for alpha-mannosidase. Intracellular beta-galactosidase, measured by histochemical staining, showed a dramatic redistribution in response to mild hyperthermia (10 min, 45 degrees C); the same effect was not observed for beta-glucuronidase. The data argue against non-specific activation of lysosomes by hyperthermia, and suggest that cells contain lysosomal subpopulations that are characterized by different heat sensitivities and variable glycosidase contents.
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PMID:Modulation of cellular glycosidase activity by hyperthermia. 183 75

The effect of swainsonine, an inhibitor of Golgi alpha-mannosidase II and lysosomal alpha-mannosidase, on the synthesis, processing, and turnover of two glycoproteins, lysosomal beta-galactosidase and lysosomal beta-glucuronidase, has been studied in cultured mouse peritoneal macrophages. No effect of the inhibitor on the relative rates of synthesis of the precursor form of either enzyme was observed. On the other hand, carbohydrate processing of beta-galactosidase and beta-glucuronidase was markedly altered by swainsonine, consistent with a blockage by the inhibitor of the removal of the alpha-1,3- and alpha-1,6-linked mannose residues which occurs in normal processing. In homogenates of both normal and swainsonine-treated cells, the precursor forms of the enzymes were found exclusively in the light membrane fraction on Percoll gradients and the mature forms exclusively in the lysosomal fractions indicating that translocation from Golgi to lysosomes and proteolytic processing in the lysosome were not impaired by the presence of abnormal oligosaccharide side chains. There was no detectable effect of swainsonine during a 4-day chase period on the total cellular turnover of these enzymes which involves two processes, secretion and degradation. In the absence of swainsonine, secretion represented about 40% of the total turnover of beta-galactosidase and about 50% with beta-glucuronidase. The presence of swainsonine increased these proportions to about 60 and 70%, respectively.
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PMID:Effect of swainsonine on the processing and turnover of lysosomal beta-galactosidase and beta-glucuronidase from mouse peritoneal macrophages. 312 86

The manB gene, coding for a unique beta-mannosidase (MANB) of Aspergillus aculeatus, was cloned from genomic and cDNA libraries, and sequenced. The gene consists of 2,811 bp encoding a polypeptide of 937 amino acid residues with a molecular mass of 104,214 Da. The A. aculeatus MANB shared amino acid sequence identity with MANB of human (24%), goat (24%), bovine (24%), and Caenorhabditis elegans (22%). When the A. aculeatus MANB was compared with other related enzymes, a Glu residue corresponding to the active site identified by the Escherichia coli beta-galactosidase and the human beta-guclonidase was conserved. This is the first fungal gene that encodes MANB.
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PMID:Cloning and sequencing of beta-mannosidase gene from Aspergillus aculeatus no. F-50. 1005 44