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

---

Query: EC:3.2.1.21 (beta-glucosidase)
3,280 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Dictyostelium discoideum strain HMW-426 has been previously shown to be defective in the proteolytic processing of the lysosomal enzyme precursor to alpha-mannosidase. We have now shown that the mutant is defective in the proteolytic processing of a second lysosomal enzyme, beta-glucosidase. Digestion of the HMW-426 alpha-mannosidase and beta-glucosidase precursors with endoglycosidase H revealed that the majority of oligosaccharide side chains on both precursors were sensitive to cleavage by this enzyme, indicating that both precursors fail to reach the Golgi apparatus. Subcellular fractionation experiments demonstrated that these two mutant precursors accumulated inside the lumen of the rough endoplasmic reticulum. The alpha-mannosidase precursor is conformationally altered, as evidenced by its abnormal protease susceptibility, suggesting that altered conformation is responsible for a generalized defect in transport of lysosomal protein precursors from the rough endoplasmic reticulum in the mutant.
...
PMID:A single mutation prevents the normal intracellular transport of multiple lysosomal proteins from the rough endoplasmic reticulum. 311 35

Trichomonas vaginalis and Tritrichomonas foetus were found to release large amounts of beta-N-acetylglucosaminidase (EC 3.2.1.30), alpha-mannosidase (EC 3.2.1.24), beta-glucosidase (EC 3.2.1.21), acid phosphatase (EC 3.1.3.2) and proteinases during axenic growth in vitro. The enzymes were released continually throughout the growth phase, with the extracellular activity being of the same order as that within the cells. There was differential release of proteinases from Trichomonas vaginalis. The subcellular localization of the hydrolases was determined by differential and isopycnic centrifugation. The intracellular enzymes were shown to be mostly located within particle populations. Centrifugation on Percoll gradients allowed the separation of sub-populations of the particles in T. vaginalis; two distinct sub-populations were apparent with equilibrium densities in 20% (v/v) Percoll of 1.035 and 1.050 g cm-3 respectively. The higher density particles were rich in the hydrolases released most abundantly, suggesting a possible link between enzyme release and these organelles. Distinct subpopulations of hydrolase-containing particles were not detected in Tritrichomonas foetus. The results demonstrate that hydrolytic enzyme release represents a major activity during trichomonad growth.
...
PMID:The release of hydrolases from Trichomonas vaginalis and Tritrichomonas foetus. 314 8

Lysosomal enzymes are initially synthesized as precursor polypeptides which are proteolytically cleaved to generate mature forms of the enzymatically active protein. The identification of the proteinases involved in this process and their intracellular location will be important initial steps in determining the role of proteolysis in the function and targeting of lysosomal enzymes. Toward this end, axenically growing Dictyostelium discoideum cells were pulse radiolabeled with [35S]methionine and chased in fresh growth medium containing inhibitors of aspartic, metallo, serine, or cysteine proteinases. Cells exposed to the serine/cysteine proteinase inhibitors leupeptin and antipain and the cysteine proteinase inhibitor benzyloxycarbonyl-L-phenylalanyl-L-alanine-diazomethyl ketone (Z-Phe-AlaCHN2) were unable to complete proteolytic processing of the newly synthesized lysosomal enzymes, alpha-mannosidase and beta-glucosidase. Antipain and leupeptin treatment resulted in both a dramatic decrease in the efficiency of proteolytic processing, as well as a sevenfold increase in the secretion of alpha-mannosidase and beta-glucosidase precursors. However, leupeptin and antipain did not stimulate secretion of lysosomally localized mature forms of the enzymes suggesting that these inhibitors prevent the normal sorting of lysosomal enzyme precursors to lysosomes. In contrast to the results observed for cells treated with leupeptin or antipain, Z-Phe-AlaCHN2 did not prevent the cleavage of precursor polypeptides to intermediate forms of the enzymes, but greatly inhibited the production of the mature enzymes. The accumulated intermediate forms of the enzymes, however, were localized to lysosomes. Finally, fractionation of cell extracts on Percoll gradients indicated that the processing of radiolabeled precursor forms of alpha-mannosidase and beta-glucosidase to intermediate products began in cellular compartments intermediate in density between the Golgi complex and mature lysosomes. The generation of the mature forms, in contrast, was completed immediately upon or soon after arrival in lysosomes. Together these results suggest that different proteinases residing in separate intracellular compartments may be involved in generating intermediate and mature forms of lysosomal enzymes in Dictyostelium discoideum, and that the initial cleavage of the precursors may be critical for the proper localization of lysosomal enzymes.
...
PMID:Inhibition of early but not late proteolytic processing events leads to the missorting and oversecretion of precursor forms of lysosomal enzymes in Dictyostelium discoideum. 314 34

In Creutzfeldt-Jakob disease (CJD), there are prominent ultrastructural alterations of the plasma membrane, which contains many glycolipids and glycoproteins. Glycosidases can degrade glycolipids and glycoproteins. Gangliosides, a subset of glycolipids, are decreased in amount at the terminal stages of CJD, and CJD infectivity is closely associated with membrane rich fractions. We therefore studied 10 glycosidases, and found a statistically significant increase in beta-xylosidase, beta-glucuronidase, N-acetyl-beta-D-glucosaminidase and N-acetyl-beta-D-galactosaminidase activities in CJD. In contrast, alpha-glucosidase, beta-glucosidase, alpha-galactosidase, alpha-mannosidase, alpha-fucosidase, and beta-galactosidase were not significantly changed. The above results are consistent with degenerative membrane changes observed morphologically, and with increased degradation of sugar residues on lipids and/or proteins. These changes may be effected by the accumulation of the CJD agent in cell membranes. We suggest that the higher activities of these enzymes in CJD may be partially responsible for some of the structural and biochemical alterations in CJD infected brains.
...
PMID:Cerebral glycosidases in experimental Creutzfeldt-Jakob disease. 328 70

Systemic release of lysosomal enzymes and local release in the pulmonary microcirculation from sequestrated and activated leucocytes could be an important factor in the development of the lung microvascular injury seen after septicaemia. The maximal activities of 11 lysosomal acid hydrolases (acid phosphatase, alpha- and beta-glucosidase, alpha- and beta-galactosidase, alpha-mannosidase, beta-acetylglucosaminidase, beta-glucuronidase, arylamidase and cathepsins B and C) were measured in serum and lung lymph from seven sheep before and after infusion of live E. coli bacteria. In the early phase of septicaemia (the first hour) the activities of eight enzymes were increased in serum and/or lung lymph (1.1 to 2X pre-infusion values). In the late phase, 3-4 h after sepsis, there were significantly elevated serum activities of beta-glucosidase (5.4X), alpha- and beta-galactosidases (2.7X, 1.5X), beta-acetylglucosaminidase (2.0X) arylamidase (1.2X) and cathespin B (1.7X). In lymph acid phosphatase (1.7X), alpha- and beta-glucosidases (1.6X, 6.4X), alpha- and beta-galactosidases (2.1X, 1.7X). Beta-acetylglucosaminidase (2.6X), and beta-glucuronidase (4.0X pre-infusion) were elevated. The findings of a heterogenicity of changes in serum and lymph activities, as well as the large molecular sizes of some of the enzymes with changed activities indicated to us that permeability changes were not major causes of increased lymph enzyme activities. The results could indicate a local release of enzymes either from sequestrated leucocytes or lung tissue due to local reactions in the lung or lung microvessels. The heterogenous changes in activities for the various lysosomal enzymes as found in the present study indicated that measurement of only one enzyme could be misleading.(ABSTRACT TRUNCATED AT 250 WORDS)
...
PMID:Lysosomal enzyme pattern in lung lymph and blood during E. coli sepsis in sheep. 329 74

A sialoglycoprotein, an integral component of the head plasma membrane of human spermatozoa, is recognized by the a-HS 1A.1 monoclonal antibody. The antigenicity is associated with the sugar moiety since: a) trypsin digestion did not affect the antigenic determinant; b) pretreatment of the cells with beta-glucosidase, alpha-mannosidase and neuraminidase completely abolished antibody binding. Endoglycosidase D and glycopeptidase F were inactive. The a-HS 1A.1 did not recognize a variety of blood-group related synthetic oligosaccharides. The species specificity was studied by indirect immunofluorescence assay. The antibody also recognized an antigen on Macaca fascicularis sperm, but failed to bind to spermatozoa of boar, bull, goat, ram, stallion, dog, rabbit, rooster, carp and eel.
...
PMID:Primate specific sialoglycoprotein of sperm head plasma membrane defined by an anti-carbohydrate monoclonal antibody. 331 19

The enzymatic activities of 53 strains of Pseudomonas cepacia were determined by using the API ZYM system. Strong alkaline phosphatase, acid phosphatase, butyrate esterase, caprylate esterase, myristate lipase, leucine arylamidase, and phosphoamidase activities were consistently detected in all strains. Weak activities were observed for valine arylamidase, beta-glucosidase, and N-acetyl-beta-glucosaminidase. No activities could be demonstrated for cystine arylamidase, trypsin, chymotrypsin, alpha-galactosidase, beta-galactosidase, beta-glucuronidase, alpha-glucosidase, alpha-mannosidase, and alpha-fucosidase. Enzymatic activities of pseudomonads may provide useful information about their pathogenesis and information for identification of Pseudomonas species.
...
PMID:Enzymatic characterization of Pseudomonas cepacia by API ZYM profile. 335 98

Nineteen hydrolytic enzymes were detected in individual adult Pergamasus longicornis (Berlese) mites--amylase, hide protease, alkali phosphatase, esterase (C4), esterase lipase (C8), lipase (C14), leucine arylamidase, valine arylamidase, cystine arylamidase, acid phosphatase, phosphoamidase, alpha-galactosidase, beta-galactosidase, beta-glucuronidase, alpha-glucosidase, beta-glucosidase, N-acetyl-beta-glucosaminidase, alpha-mannosidase, and alpha-fucosidase. All but the phosphatases were detected for the first time. Tryptic and chymotryptic activity were consistently not demonstrable. Comparisons are made with saprophagous mites. No clear enzymic specialization for predation was found.
...
PMID:Digestion in the soil predatory mite Pergamasus longicornis (Berlese) (Acari: Mesostigmata: Parasitidae)--detectable hydrolases. 356 25

In human freshly prepared platelets the following lysosomal enzymes were studied: alpha-mannosidase, alpha-fucosidase, beta-galactosidase, beta-glucosidase, beta-glucuronidase, beta-N-acetylglucosaminidase and acid phosphatase. For each of the examined enzymes the conditions providing maximal activity (pH, buffer), kinetic parameters (saturating substrate concentration and Km) as well as heat stability were established. On the basis of these parameters it is suggested that many of the serum glycohydrolases may be platelet derived.
...
PMID:Lysosomal enzymes in human platelets. 383 17

Evidence has been found for a generalized change in the post-translational modification of lysosomal enzymes during development of Dictyostelium discoideum. The physical and antigenic properties of four developmentally regulated lysosomal enzymes, N-acetylglucosaminidase, beta-glucosidase, alpha-mannosidase, and acid phosphatase, have been examined throughout the life cycle. In vegetative cells, a single major isoelectric species is detected for each enzymatic activity on native nonequilibrium isoelectric focusing gels. Between 6 and 10 hr of development, all activities, including the preformed enzyme, become less negatively charged, resulting in a modest but reproducible shift in the isoelectric focusing pattern. This alteration is not detected by native gel electrophoresis at constant pH. As development continues, the specific activity of beta-glucosidase, alpha-mannosidase, and acid phosphatase continues to increase and coincidentally, new, less acidic isozymic bands of activity can be observed on both gel systems. Some of these new isozymes accumulate preferentially in anterior cells, while others accumulate preferentially in posterior cells of migrating slugs. N-Acetylglucosaminidase does not increase in specific activity late in development and no new isozymic species appear. Using a monoclonal antibody that reacts with sulfated N-linked oligosaccharides shared by vegetative lysosomal enzymes in D. discoideum, the antigenicity of the developmental isozymes has been characterized. All of the enzymatic activity present during vegetative growth and early development is immunoprecipitable. However, the less negatively charged isozymes that accumulate after aggregation are not recognized by the antibody. Nonantigenic acid phosphatase and alpha-mannosidase are found in both anterior and posterior cells from migrating pseudoplasmodia. Since each enzyme is coded by a single structural gene, these results suggest that the isozymes present late in development arise from the synthesis of the same polypeptides with altered post-translational modifications. The appearance of anterior and posterior specific isozymes is likely to be the result of cell type specific changes in the glycoprotein modification pathway for newly synthesized proteins.
...
PMID:Developmental changes in the modification of lysosomal enzymes in Dictyostelium discoideum. 391 96


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>

---