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:3.2.1.31 (beta-glucuronidase)
7,680 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Cupric ions were administered subcutaneously to male Sprague-Dawley r rats at a single dose of 200 mumol/kg. At 24 hr after administration, a remarkable increase of total and free cholesterol was seen in the rat serum. Also, when lecithin-cholesterol acyltransferase (LCAT) (E.C. 2.3.1.43) activity was expressed as the percentage of the total serum that free cholesterol esterified, the acyltransferase activity in rats treated with cupric ions showed a slight decrease while the triglyceride content in rat serum and liver decreased by 54% and 61%, respectively. However, the content of hepatic cholesterol in rats treated with cupric ions did not show such a marked change. On the other hand, acid cholesteryl ester hydrolase activity (Acid CEH) (E.C. 3.1.1.14) in liver lysosomes of rats treated with cupric ions showed a marked decrease with increasing cupric ion concentration both in vivo and in vitro. Furthermore, cupric ions caused a marked release of the lysosomal enzymes cathepsin D and beta-glucuronidase into the cytosolic fraction. The changes in acid cholesteryl ester hydrolase activity induced by cupric ions appear to be a direct effect of cupric ions on the enzyme. These results suggest that excessive cupric ion concentrations could cause various disorders in lipid metabolism.
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PMID:Effect of cupric ions on serum and liver cholesterol metabolism. 345 Oct 6

Considerable progress has been made in the localization of chemical substances within the gas-exchange zones of vertebrate lungs since cytochemical techniques suitable for use with the electron microscope have been developed. The light microscope, an instrument with an effective resolution limit of about 0.2 micron, is ill-suited for studying regions such as these where small tissue elements are arranged in a complex manner. A wide range of acid hydrolases have been detected in the vacuoles and dense bodies of alveolar macrophages by means of cytochemical techniques. The enzymes demonstrated in this way include acid phosphatase, aryl sulphatase, cathepsin D, beta-glucuronidase, acetyl glucosaminidase, nonspecific esterase, dipeptidyl peptidase II and dipeptidyl peptidase IV. Such enzymes are, of course, to be expected in the lysosomes of cells which have a primary phagocytic role. Nevertheless, it must be confessed that very little is yet known about the actual mechanism of phagocytosis or of the fate of the digested material. It is fortunate, however, that some of the tools which are likely to be of value in research on these aspects of macrophage function are currently being developed. Of particular interest in this connection are the immunocytochemical techniques which permit the localization of surface-associated antigens and intracellular contractile proteins. It must be emphasized that phagocytosis is not the only function of macrophages in the gas-exchange zone of the lung. These cells are thought to be involved in the presentation of exogenous antigenic material to the reactive cells of the lymphoid system. Recent research has also indicated that mammalian alveolar macrophages synthesize a diverse range of substances. Furthermore, the elastases associated with pulmonary macrophages are now thought to be involved in the pathogenesis of emphysema. All of the above-mentioned activities are of great biological and clinical significance and, consequently, merit the cytochemists' attention in future. The epithelial lining of the greater part of the pulmonary gas-exchange area is composed of type I pneumonocytes. In terms of ultrastructure, these are very specialized cells; their extensive and highly-attenuated cytoplasmic processes form the outer layer of the air-blood barrier. No special carrier systems have been identified within type I pneumonocytes and this is in keeping with the claims that oxygen is transferred across the alveolar tissue barrier by a process of simple diffusion. Type II pneumonocytes, in contrast, have considerable metabolic activity.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Cytochemistry of the gas-exchange area in vertebrate lungs. 355 66

A quantitative study was carried out on the lysosomal enzyme activities of the bovine corneal endothelium-Descemet's membrane preparation. The corneal endothelium and Descemet's membrane were peeled off together. Cathepsin D was assayed using hemoglobin as substrate; N-acetyl-beta-D-glucosaminidase, beta-glucuronidase, acid phosphatase, and alpha-mannosidase were also examined using p-nitrophenyl derivatives as substrate. The proportions of N-acetyl-beta-D-glucosaminidase, cathepsin D, and beta-glucuronidase of the Descemet's membrane-endothelium complex were particularly high: 11.5%, 12.6%, and 12.5% of the whole cornea, respectively. Corneal endothelial cells also showed high activities of acid phosphatase and alpha-mannosidase (3.8%, and 5.0% of the whole cornea, respectively), while the protein and DNA contents were 0.5% and 0.5% in the complex. Lysosomal enzyme activities in the complex were also compared with those in other ocular tissues and were determined by the same methods at the same time.
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PMID:Lysosomal enzyme activities of the bovine corneal endothelium. 371 Jan 95

The activities of acid phosphatase, N-acetyl-beta-D-glucosaminidase, alpha-mannosidase, alpha-fucosidase, beta-glucuronidase, arylsulfatase, and cathepsin D were biochemically investigated in the bovine cornea by separating the tissue into two layers, epithelium and stroma-endothelium. Acid phosphatase, alpha-mannosidase, alpha-fucosidase, and arylsulfatase disclosed much higher activities in the epithelial layer than in the stroma-endothelial layer. The other enzymes showed little difference in enzyme activity between the two layers.
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PMID:Acid hydrolases in the bovine corneal epithelium. 375 93

Lysosomal enzyme activities in pancreatic islets of obese hyperglycemic ob/ob mice aged 3 to 6 months were investigated and compared with those of normal lean NMRI mice of the same age. It was observed that the glycogenolytic glucose-producing hydrolase acid amyloglucosidase displayed a fivefold higher activity in the islets of obese mice than in the islets of normal NMRI mice. However, other islet lysosomal enzyme activities measured, such as N-acetyl-beta-D-glucosaminidase and beta-glucuronidase, were of the same magnitude in both obese and lean mice. A starvation period of 24 hours induced a significant depression of islet acid amyloglucosidase activity in obese as well as lean mice, whereas the activities of N-acetyl-beta-D-glucosaminidase and beta-glucuronidase were unaffected. Further, the activities of other types of islet lysosomal enzymes, such as acid phosphatase and cathepsin D, were also measured in obese mice. These activities were not found to be affected by the actual fasting period. A good correlation (r = 0.815; P less than 0.01) was observed between islet acid amyloglucosidase activity and plasma insulin concentrations in obese mice, whereas no such relationship was apparent with regard to other islet lysosomal enzyme activities recorded. Acid amyloglucosidase activity in liver tissue of the obese mouse was about 30 times lower than that of islet tissue. Further, the activity of liver amyloglucosidase was of the same order of magnitude in obese and lean mice. Similarly, other lysosomal enzyme activities in the liver of obese and lean mice were not strikingly different.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Lysosomal enzyme activities in pancreatic islets from normal and obese hyperglycemic mice. 391 27

Thyrotropin releasing hormone (TRH) has been reported to reverse hypotension induced by a variety of agents and thus it has been suggested to be of therapeutic value in circulatory shock. We have investigated TRH (2 mg/kg bolus plus 2 mg/kg/hr infusion) in both hemorrhagic (cats) and traumatic shock (rats). TRH induced a pressor effect of 23 +/- 8 mm Hg (p less than 0.05) in cats and 19 +/- 3 mm Hg (p less than 0.01) in rats during hypotension. However, this transient (10-15 min) response did not result in any sustained improvement in the cardiovascular status of the animals in either shock model when compared to the vehicle. In addition, TRH did not attenuate any of the biochemical indices of the severity of the shock state (i.e., plasma amino-nitrogen concentrations, or plasma cathepsin D and MDF activities) nor did it improve survival time in traumatic shock (2.8 +/- 0.4 vs. 2.0 +/- 0.2 hours). Furthermore, TRH resulted in a significant blunting of the maximum post-reinfusion superior mesenteric artery flow and enhanced beta-glucuronidase release from liver lysosomal preparations in vitro. These potentially detrimental effects in conjunction with the lack of any overt protective effect under the conditions existing in these two shock models, do not provide evidence that TRH is beneficial as a therapeutic agent in circulatory shock.
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PMID:Lack of effect of thyrotropin releasing hormone (TRH) in circulatory shock. 393 48

Macrophages carry receptors on their surface for acetylated low density lipoprotein (ac-LDL). Receptor-mediated endocytosis of ac-LDL is followed by intracellular cholesterol accumulation. We investigated whether occupation of these binding sites evokes the release of hydrolytic enzymes from mouse peritoneal macrophages cultured for up to 48 h. ac-LDL at concentrations ranging from 25-250 micrograms protein/ml was noted to promote in a dose-dependent fashion secretion of the neutral proteinase elastase (EC 3.4.21.37) and the lysosomal acid hydrolases N-acetyl-beta-glucosaminidase (EC 3.2.1.30), beta-glucuronidase (EC 3.2.1.31), beta-galactosidase (EC 3.2.1.23), alpha-mannosidase (EC 3.2.1.24) and cathepsin D (EC 3.4.23.5). This stimulatory effect was non-cytotoxic. LDL modified by treatment with malondialdehyde was also capable of augmenting enzyme liberation into culture supernates. These findings may have implications for some aspects of the atherosclerotic process.
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PMID:Chemically modified low density lipoproteins as inducers of enzyme release from macrophages. 400 64

Postnuclear supernates from homogenates of skeletal muscle from rats subjected to starvation, injections of Triton WR-1339, dextran-500, and dextran + corticosterone were fractionated by means of rate and isopycnic zonal centrifugation in sucrose-0.02 M KCl gradients. Zonal fractions were analyzed for protein, RNA, cytochrome oxidase, and up to six acid hydrolases. The results indicate the presence of two groups of lysosome-like particles. One group contributes approximately 95% of the cathepsin D and acid phosphatase activity and 75% of the acid ribonuclease, beta-glucuronidase, and arylsulfatase activity in muscle. It is characterized by a modal equilibrium density of 1.18 that is decreased by starvation, but is not shifted by dextran-500 or Triton WR-1339. The second group has a higher proportion of acid ribonuclease, beta-glucuronidase, and arylsulftase; the equilibrium density can be shifted by dextran-500 and Triton WR-1339. It is suggested that this group of lysosomes is derived from macrophages and other connective tissue cells, whereas the former group represents lysosome-like particles from muscle cells.
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PMID:Lysosomes in skeletal muscle tissue. Zonal centrifugation evidence for multiple cellular sources. 432 73

Rabbit synovial fibroblasts in monolayer culture secrete a specific collagenase and a neutral endopeptidase into their serum-free culture medium. The rate of secretion of these two enzymes is increased after the ingestion and storage of latex particles within the vacuolar system of the cells. The increased rates of secretion of the neutral enzymes are stable for over 2 wk in the absence of a further phagocytic bout. In constrast there is little change in the extracellular levels of two lysosomal hydrolases, cathepsin D and beta-glucuronidase. The increase in the secretory rates for the two neutral enzymes is related to the number of latex particles ingested by the cells, and increases of up to 12-fold over the nonphagocytosing cultures were observed. A variety of other materials including mycostatin particles and dextran sulfate also induced increases in the secretion of collagenase. These results are discussed in relation to the turnover of connective tissue matrix macromolecules.
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PMID:Stimulation by endocytosis of the secretion of collagenase and neutral proteinase from rabbit synovial fibroblasts. 437 92

1. Rat kidney lysosomal glycoproteins, prelabelled in the N-acetylneuraminic acid and polypeptide portions with N-acetyl[(3)H]mannosamine and [(14)C]lysine, or with N-acetyl-[(14)C]glucosamine, were incubated under various conditions. Autolytic cleavage of labelled N-acetylneuraminic acid and peptide was maximum at pH5.0. 2. N-Acetylneuraminic acid was released more rapidly than peptide during incubation at 37 degrees or 4 degrees C at pH5. p-Nitrophenyloxamic acid, an inhibitor of bacterial neuraminidase (Edmond et al., 1966), inhibited the cleavage of N-acetylneuraminic acid and peptide, and also inhibited cathepsin D activity. 3. Galactono-, mannono-, and glucono-lactone, inhibitors of the corresponding glycosidases, blocked the autolytic cleavage of N-acetyl[(14)C]glucosamine and protein without inhibiting beta-N-acetylhexosaminidase or cathepsin D activity. These findings suggest that the carbohydrate side chains protect the polypeptide portion of the lysosomal glycoproteins against proteolytic attack by lysosomal cathepsins. 4. In electrofocusing experiments, autolysis was minimized by adding 0.1% p-nitrophenyloxamic acid to the media used for extraction and electrofocusing, and by maintaining an alkaline pH (pH8.8-9) during extraction and dialysis. Arylsulphatase occurred in two forms with pI values of 4.4 and 6.4-6.7, and beta-glucuronidase in two forms with pI values of 4.4 and 6.1. When [(14)C]lysine and N-acetyl[(3)H]mannosamine were given to rats 1.5 and 1 h before killing, (14)C and (3)H were largely restricted to highly acidic glycoprotein species with pI values of 2.1-5.1. 5. When a lysosomal extract was adjusted to pH5 and incubated at 20 degrees C for 16h and then at 37 degrees C for 1 h before electrofocusing, 32 and 58% of the labelled peptide and N-acetylneuraminic acid was cleaved and the pI values of the labelled glycoproteins were markedly increased. About 80% of the acidic form of arylsulphatase and beta-glucuronidase was recovered with the basic form, and the pI of the basic form of both enzymes rose to 7.0. Similar, though less marked changes, were observed when a lysosomal extract was kept at pH5 for 2h at 4 degrees C before electrofocusing. 6. When an acidic lysosomal fraction (pI4.2-4.6) was incubated at pH5 for 2.5h and refocused, 80% of the arylsulphatase now occurred in two forms with pI values of 5 and 6.4. When a basic lysosomal fraction (pI5.8-6.4) was similarly incubated, the pI of arylsulphatase increased from 6.4 to 7.2. The relative increase in pI of arylsulphatases was accompanied by a proportional loss of N-acetylneuraminic acid from the glycoprotein associated with these forms. 7. These experiments show that lysosomal glycoproteins and two representative hydrolases, when exposed to a mildly acidic pH, readily undergo autolytic degradation and their pI values increase. These observations may have a bearing on the origin of the molecular heterogeneity of the lysosomal enzymes.
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PMID:Autolysis of glycoproteins in rat kidney lysosomes in vitro. Effects on the isoelectric focusing behaviour of glycoproteins, arylsulphatase and beta-glucuronidase. 445 20


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