Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.2.1.21 (beta-glucosidase)
 3,280 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Optimal assay conditions are described for 8 hydrolases of Euglena gracilis var. bacillaris, SM-L1 (streptomycin-bleached) strain, 7 of which have an acid pH-optimum. Acid-phosphatase, beta-galactosidase, beta-glucosidase, b-fucosidase, cathepsin D, RNase, DNase, and an esterase are active in cell homogenates. Amylase has very low activity, and beta-glucuronidase, arylsulfatase, beta, N-acetyl-glucosaminidase, alpha-fucosidase, and alpha- and beta-mannosidase are inactive.
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PMID:Hydrolytic enzymes of Euglena gracilis: characterization and activity as a function of culture age and carbon deprivation. 0 4

Six patients with liver metastases from carcinoid or colon carcinoma underwent hepatic derterialization. This operation, known to cause both tumor necrosis and liver cell damage, caused considerable increases of several lysosomal acid hydrolases in the circulation. Thus, beta-glucosidase showed a small temporary increase during the operation, followed by a slower but higher reaction reaching a maximum 12 to 36 hours postoperatively. Similar reactions were noted for beta-glucuronidase, acid phosphatase, beta-galactosidase, arylsuphatase A, and N-acetyl-beta-glucosaminidase while no reactions were found for cathepsin D. Very high enzyme levels occurred in a patient dying from bleeding complications in the postoperative period.
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PMID:Plasma activities of lysosomal enzymes after hepatic dearterialization in man. 0 1

Rat embryo fibroblasts, grown in Eagle's MEM with 10% serum, showed a rapid increase in autophagic vacuoles when placed in MEM with 0-1% serum. Concurrent with this response, degradation of cellular proteins showed a 2-fold increase. We did not find any increases in cathepsin D, beta-glucuronidase, beta-galactosidase, and beta-glucosidase, or proteolytic activity of cell homogenates at pH 3.7 towards endogenous substrates. Homogenates prepared in 250 mM sucrose at pH 7.0 showed a 40% increase in protein breakdown. These data support the hypothesis that the induced increase in proteolysis, characteristic of cells placed in a nutritionally deficient medium, is effected by an activated vacuolar apparatus (lysosomes and autophagic vacuoles). We suggest, however, that this mechanism is distinct from normal protein turnover in the cell, but can be rapidly induced by appropriate alterations in the cellular environment. Finally, this induced proteolytic mechanism is not dependent upon an increase in lysosomal enzymes, but rather a structural alteration within the cell which effects a transfer of cellular proteins into the vacuolar apparatus.
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PMID:Role of the vacuolar apparatus in augmented protein degradation in cultured fibroblasts. 2 52

The nonselective beta-blocker propranolol and the selective beta 1-adrenoblocker flusoxolol were tested for their effects on the activities of acid phosphatase, acid DNAase, cathepsin D, beta-glucosidase and beta-galactosidase in intact rat ventricular myocardial homogenates. The two drugs were found to have the most noticeable effect on the activity of three enzymes under study: acid phosphatase, beta-glucosidase and beta-galactosidase. They were able to stabilize lysosomal membranes during long-term homogenate preincubation at 37 degrees S. It is suggested that the mechanism of action of the drugs on intact rat ventricular myocardial lysosomes under the conditions of the study involves the binding of both propranolol and flusoxolol to beta-adrenoceptors on the lysosomes.
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PMID:[The effect of propranolol and flusoxolol on the lysosomal enzyme activity of the rat ventricular myocardium]. 136 45

The influence of cardioselective beta-blockers, practolol and atenolol, on acid phosphatase, acid deoxyribonuclease, cathepsin D, beta-glucosidase and beta-galactosidase activities was studied in homogenates of intact rat ventricular myocardium. In the presence of drugs (1 x 10(-9)-1 x 10(-5) M) the activities of acid phosphatase, cathepsin D, beta-glucosidase and beta-galactosidase tended to diminish but the activity of acid deoxyribonuclease tended to increase. Some differences in the influence of drugs on the enzyme activities were removed by prolongation of preincubation of homogenates with drugs. It is supposed that the mechanism of influence of beta-blockers on lysosomes of the intact rat ventricular myocardium in conditions of this study includes the specific drug binding to beta-adrenergic receptors situated on lysosomes.
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PMID:[The effect of practolol and atenolol on the lysosomal enzyme activity of the ventricular myocardium of rats]. 166 75

The changes in the activities of certain lysosomal hydrolases, viz., beta-glucuronidase, beta-N-acetylglucosaminidase, beta-galactosidase, beta-glucosidase, alpha-glucosidase, alpha-galactosidase, alpha-mannosidase, cathepsin B, cathepsin D, and collagenolytic cathepsin, in serum and heart of rats subject to myocardial infarction with isoproterenol, were studied during the periods of peak infarction and recovery. The activities of all the enzymes assayed exhibited a significant increase both in serum and in heart at peak infarction stage and these levels returned to normal during the stage of recovery and repair. The infiltration of inflammatory cells at the infarct regions and the altered lysosomal fragility are probably responsible for the increased activity of the enzymes studied. This may also bring about the catabolism of connective tissue constituents as reported in literature.
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PMID:Influence of isoproterenol-induced myocardial infarction on certain glycohydrolases and cathepsins in rats. 201 10

Acute starvation of the wild-type of the nematode Caenorhabditis elegans depresses the level of cathepsin D by 65% within 4-8 h and the level of the thiol cathepsins Ce1 and Ce2 to about the same extent after 24 h. There is no parallel loss of lysosomal beta-glucosidase or beta-hexosaminidase activities. In strains which are chronically starved as a result of mutations which compromise feeding behaviour (unc-52) or nutrient uptake into the intestinal cells (daf-4), cathepsin D levels are decreased to about 15% of the level in fully fed wild-type animals. We suggest that the decline in the cathepsin D level results from autodigestion when alternative protein substrates are depleted in the lysosomes.
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PMID:Regulation of proteinase levels in the nematode Caenorhabditis elegans. Preferential depression by acute or chronic starvation. 251 5

In addition to their general function in cellular homeostasis, thyroid lysosomes play an essential role in the biosynthesis of thyroid hormones by cleaving the macromolecular prohormone, thyroglobulin. In the present work, we have attempted to determine whether the enzyme composition of thyroid lysosomes differs from that of lysosomes from other tissues. Lysosomal enzymes, cathepsin D, beta-D-galactosidase, beta-D-glucosidase, alpha-D-mannosidase, alpha-L-fucosidase, hexosaminidase, and arylsulfatase A and B, were assayed in crude fractions from various pig tissues, heart, brain, liver, kidney, thyroid, adrenals, ovary, and spleen. It appeared that the specific activity of arylsulfatase A was at least 20 times higher in the thyroid than in most other tissues. Thyroid lysosomes purified by isopycnic centrifugation on Percoll gradients contained two major polypeptides with apparent molecular weights of 58,000 and 54,000 representing about 30% of the total protein. These polypeptides were glycosylated and were exclusively found in the intralysosomal soluble fraction obtained by osmotic pressure-dependent lysis. By fractionating intralysosomal soluble proteins by velocity sedimentation on sucrose gradients or gel permeation chromatography we identified a thyroid arylsulfatase A holoenzyme which corresponds to a 120,000 Mr species. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis analyses of the gradient or column fractions showed that the 120-kDa protein peak with arylsulfatase A activity essentially contained the 58- and 54-kDa polypeptides in equivalent amounts. In conclusion, arylsulfatase A, a heterodimer of 120 kDa composed of two nonidentical subunits, is the major protein component of thyroid lysosomes. The superabundance of this protein in purified thyroid lysosomes is related to the very high specific activity of the enzyme in the thyroid as compared to other tissues.
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PMID:Evidence for the presence of a very high concentration of arylsulfatase A in the pig thyroid: identification of arylsulfatase A subunits as the two major glycoproteins in purified thyroid lysosomes. 256 93

Adler and Martin (1983, Curr. Eye Res. 2, 359-66) found cathepsin D to be present in crude preparations of bovine interphotoreceptor matrix (IPM). The purpose of the present study was to determine, by investigating several acid hydrolases in purer IPM samples, whether hydrolytic enzymes abundant in RPE lysosomes were present also as normal components of the IPM. IPM was prepared from bovine eyes by the introduction of a small bleb of buffer between the neural retina and the RPE. These IPM samples were free from significant contamination by surrounding tissues; they contained IRBP as their only major protein, and had negligible amounts of lactate dehydrogenase and ROS-specific proteins. Most acid hydrolases were assayed fluorometrically by measuring the 4-methylumbelliferone released upon hydrolysis of appropriate derivatives; the substrate for cathepsin was hemoglobin. The amounts of the enzymes found in the IPM were far from uniform and could not be correlated with enzyme activities in either RPE or retina homogenates. The hydrolases in the IPM varied in amount from beta-galactosidase (28% of the RPE level), through N-acetyl-beta-glucosaminidase (20%), alpha-fucosidase (15%), beta-glucuronidase (12%), alpha-glucosidase (8%), cathepsin D (7%), alpha-mannosidase (7%), down to beta-glucosidase, acid phosphatase, and acid lipase (trace amounts, less than 1%). These results agree with the relative amounts of enzymes found by Wilcox (1987) to be secreted into the medium by cultured human RPE cells. Furthermore, the rank order of hydrolases in the IPM is the same as that for hydrolases secreted (but not recaptured) by human fibroblasts in I-cell disease. The conclusion from these correlations is that lysosomal enzymes are probably secreted, as a normal process, by the RPE into the IPM, where they may have a role in digesting shed outer segments and in catabolizing IPM components.
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PMID:Selective presence of acid hydrolases in the interphotoreceptor matrix. 261 85

To understand the molecular mechanisms of damages appearing in biological membranes in the process of cellular aging, changes in the rate of catabolic processes in Mycoplasma cells have been studied. This study has revealed that the aging of Acholeplasma laidlawii culture is accompanied by a decrease in the activity of such catabolic enzymes as DNA-ase, RNA-ase, cathepsin D and beta-glucosidase. A considerable increase in the duration of the half-life of membrane proteins has been registered, which is indicative of a decrease in their turnover rate. The electrophoretic separation of membrane proteins has revealed essential changes in their properties. Such decline in the functional activity of the plasma membrane of Mycoplasma cells at the stationary phase is probably due to the inactivation of membrane enzymes and to the decreased rate of their turnover.
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PMID:[Dependence of membrane protein turnover in Mycoplasma cells on the age of the culture]. 311 36


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