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)

The mitochondrias of the hyalocytes contain lactic dehydrogenase but no glucose-6-phosphate dehydrogenase, so that only aerobic respiration is possible. Among the lysosomal enzymes, acid phosphatases and beta-glucuronidase are found, the latter facilitating the turnover of the hyaluronic acid. There is no galactosidase, as the hyaluronic acid of the vitreous does not contain galactose.
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PMID:Histoenzymologic study of hyalocytes in tissue culture. 9 Apr 62

The effect of low and high doses of ascorbic acid on glycosaminoglycan and lipid metabolism was studied in guinea pigs fed both normal and atherogenic diets. The high dose of ascorbic acid (25 mg/100 g body weight/day) decreased the cholesterol level in the liver and aorta but not in the serum in animals fed the normal diet in comparison with those fed the low dose of ascorbic acid (0.1 mg/100 g body weight/day). In animals fed the atherogenic diet, cholesterol decreased in the serum and liver, but not in the aorta. Serum triglycerides were not affected by the dose of ascorbic acid in the group on the normal diet, but in the animals receiving the atherogenic diet, the high dose of ascorbic acid caused serum triglycerides to decrease when compared with the low dose. Hepatic and aortic triglycerides decreased in groups on normal and atherogenic diets receiving the high dose of ascorbic acid. Lipoprotein lipase activity was not affected in the aorta by the dose of ascorbic acid either in the normal or atherogenic diet group. It was increased in the liver and heart in both the groups receiving the low dose of ascorbic acid but decreased in the high dose group. The concentration of all the glycosaminoglycans significantly increased in the aorta of animals on normal diet receiving the high dose of ascorbic acid when compared with the low dose group. In the group on the atherogenic diet, hyaluronic acid was not affected, but all the sulphated glycosaminoglycans increased in the animals receiving the high dose when compared with those receiving the low dose. In the liver all the sulphated glycosaminoglycans increased while hyaluronic acid decreased in both the normal and atherogenic diet groups receiving the high rather than the low dose of ascorbic acid. L-Glutamine:D-fructose-6-phosphate aminotransferase and UDPG dehydrogenase, two key enzymes in the biosynthesis of precursors of glycosaminoglycans, were studied in relation to the dose of ascorbic acid. Hepatic aminotransferase activity was higher both in the normal and atherogenic diet groups when receiving the high rather than the low dose of ascorbic acid. UDPG dehydrogenase was not affected by the dose of ascorbic acid. The activities of the degrading enzymes -- hyaluronidase, beta-glucuronidase, beta-hexosaminidase and aryl sulphatase -- significantly increased both in the normal and atherogenic diet groups when receiving the low rather than the high dose of ascorbic acid. The concentration of PAPS, sulphate activity and sulphotransferase activity were all increased in both the normal and atherogenic diet groups receiving the high dose of ascorbic acid.
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PMID:Ascorbic acid and glycosaminoglycan and lipid metabolism in guinea pigs fed normal and atherogenic diets. 12 67

A kinetic analysis of the stepwise alternating action of beta-glucuronidase and beta-acetylglucosaminidase on oligosaccharides and dextrins derived from hyaluronic acid was undertaken, for better definition of the contribution of this process to hyaluronate catabolism. Production of monosaccharide from larger dextrins by action of either enzyme is powerfully inhibited by electrolyts. In the study, as in mammalian tissues, beta-glucuronidase is present in excess so that the concentration of beta-acetylglucosaminidase is rate controlling in the action on dextrin substrates. For this action, Vmax shows limited variation with ionic strength or molecular weight of substrate. At ionic strength 0.03, but not 0.18, Km decreases some 100-fold for increase of molecular weight from 2,000 to 15,000. It is specifically this decrease in Km that accounts for the prominent electrolyte inhibition observed with larger dextrins. The extremely low values of Km are attributed to multiple ionic enzyme-substrate interactions at sites remote from the catalytic center. The previously reported stimulation by electrolyte of the action of beta-glucuronidase and beta-acetylglucosaminidase on aryl glycosides, studied briefly, is apparently unrelated to the electrolyte effects seen with dextrins. The catabolic contribution of beta-glucuronidase and beta-acetylglucosaminidase appears to be restricted to hydrolysis of the smaller oligosaccharides produced by action of hyaluronidase, since, for any reasonable assumptions regarding cellular environment, the extent of their action on polymeric hyaluronate or larger dextrins must be limited.
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PMID:Concerted action of beta-glucuronidase and beta-acetylglucosaminidase on hyaluronodextrins. 24 Jun 46

Glycosidases capable of degrading intercellular matrix components were investigated in a 32P induced rat osteosarcoma. Homogenates of ossifying tumour were shown to readily degrade hyaluronic acid, chondroitin sulphates 4 and 6 but not dermatan sulphate. High levels of the exoglycosidases, beta-glucuronidase and beta-N-acetylglucosaminidase were found in tumour homogenates, and it was demonstrated that these enzymes contribute to the degradation of high molecular weight hyaluronic acid. The levels of these enzymes were compared with activities found in homogenates of neonatal bone and muscle surrounding tumours. Exoglycosidases, but not hyaluronidase, were found to be produced by cultures of osteosarcoma in vitro.
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PMID:Endo- and exoglycosidases in an experimental rat osteosarcoma. 27 64

Oligomers of hyaluronic acid were prepared by digestion of hyaluronic acid from rooster combs with testicular hyaluronidase (hyaluronate 4-glycanohydrolase, EC 3.2.1.35), leech head hyaluronidase (hyaluronate 3-glycanohydrolase, EC 3.2.1.36), and with fungal hyaluronidase (hyaluronate lyase from Streptomyces hyalurolyticus). The oligomers were fractionated by gel permeation, using Sephadex G-50. Oligomers isolated after incubation of the hyaluronic acid with the testicular hyaluronidase were further modified. To prepare oligomers with N-acetylglucosamine at both ends, terminal nonreducing glucuronic acid residues were removed with beta-glucuronidase. Reducing terminal N-acetylglucosamine residues were removed by reaction under mildly alkaline conditions. The reducing terminal N-acetylglucosamine residues were also reduced with sodium borohydride to form N-acetylglucosaminitol. The potentials of the various oligosaccharides to bind to the proteoglycan from bovine nasal septum cartilage were estimated by determining their effectiveness as inhibitors of the proteoglycan-hyaluronate interaction. The present study shows that, to bind maximally to the proteoglycan, the hyaluronate oligosaccharide must be at least 10 sugar residues in length and be terminated at the nonreducing and reducing ends with a glucuronate residue and an N-acetylglucosamine residue, respectively. Sugar residues extended beyond this basic decasaccharide, do not interact with the hyaluronate binding site on the proteoglycan.
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PMID:Interactions of cartilage proteoglycans with hyaluronate. Inhibition of the interaction by modified oligomers of hyaluronate. 43 8

Oligosaccharides derived from chondroitin 4-sulfate (Ch4-S) and chondroitin were digested by canine liver lysosomes under acidic conditions. The degree of digestion of Ch4-S by hyaluronidase and beta-glucuronidase was examined on the basis of types of the digestion products. Tetradeca- and dodecasaccharides derived from Ch4-S and chondroitin were first digested by hyaluronidase, while the octasaccharide was hydrolyzed by beta-glucuronidase. Decasaccharide was degraded by both hyaluronidase and beta-glucuronidase. The results showed that decasaccharide from Ch4-S served as the largest-molecular-weight substrate for beta-glucuronidase in the degradation of Ch4-S by the enzymes of lysosomes in contrast to the results of the digestion studies of hyaluronic acid (HA). The contribution of beta-glucuronidase to the depolymerization of chondroitin and HA by hyaluronidase was examined in the presence of saccharo-1,4-lactone, a specific inhibitor of beta-glucuronidase, in the reaction mixture. The depolymerization of chondroitin by hyaluronidase was significantly reduced by the addition of saccharo-1,4-lactone. From the results, it is suggested that beta-glucuronidase contributes to the degradation of the even-numbered oligosaccharides which inhibit the action of hyaluronidase in the depolymerization of Ch4-S.
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PMID:Contribution of beta-glucuronidase to the degradation of chondroitin 4-sulfate by canine liver lysosomal enzymes. 44 79

1. Incubation of rabbit tracheal explants with N-[(3)H]acetyl-d-glucosamine and N-acetyl-d-[1-(14)C]glucosamine led to labelling of a number of soluble macromolecular products separable from the medium, after papain digestion, by ion-exchange chromatography. 2. With N-acetyl-d-[1-(14)C]glucosamine in the incubation medium, a neutral glycoprotein, two acidic glycoprotein fractions, hyaluronic acid and a glycosaminoglycan fraction were obtained and all were radioactively labelled. Similar labelling occurred with N-fluoroacetyl-d-[1-(14)C]glucosamine or N-fluoro[(3)H]acetylglucosamine as precursor. 3. Maximal labelling was obtained at 96h after incubation of cultures. N-Fluoroacetyl-glucosamine under these conditions was incorporated into hyaluronate less efficiently than N-acetylglucosamine. 4. With N-fluoroacetyl-d-[1-(14)C]glucosamine as precursor, a hyaluronate component was separated that on enzymic degradation by glycosidases (hyaluronidase, beta-glucuronidase and N-acetyl-beta-hexosaminidase) yielded a (14)C-labelled oligosaccharide fraction together with N-acetyl-d-[1-(14)C]glucosamine and N-fluoroacetyl-d-[1-(14)C]glucosamine, consistent with some exchange of N-acetyl groups having occurred. 5. The results on enzymic degradation of labelled macromolecules by glycosidases suggest that the presence of incorporated N-fluoroacetyl side chains may render the hyaluronate analogue more resistant to hyaluronidase.
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PMID:Incorporation of N-fluoroacetyl-D-glucosamine into hyaluronate by rabbit tracheal explants in organ culture. 51 60

The effect of orchidectomy in male rabbits and administration of testosterone to orchidectomized animals on the metabolism of glycosaminoglycans (GAG) has been studied. The response of the different GAG fractions in the aorta varies with the nature of the GAG, and in some cases is different in different segments of the aorta. Orchidectomy produced an increase in hyaluronic acid fraction, decrease in heparin sulphate fraction, and no response in the chondroitin sulphate A fraction in the aortic arch, thoracic aorta, and abdominal aorta. Chondroitin sulphate C and chondroitin sulphate B fractions decreased only in the abdominal aorta and were not significantly altered in the other two segments, while heparin fraction decreased only in the thoracic aorta and was not affected in the other segments. Administration of testosterone to the orchidectomized animals counteracted these changes in the aortic GAG fractures. The enzymes concerned with the synthesis of precursors of GAG--L-glutamine:D-fructose-6-phosphate aminotransferase, UDPG dehydrogenase, and UDPG pyrophosphorylase-- all decreased in the orchidectomized animals; testosterone administration increased their activity in the orchidectomized animals. Enzymes concerned with degradation of GAG--beta-glucuronidase, beta-hexosaminidase, aryl sulphatase, cathepsin, and hyaluronidase--increased in the orchidectomized and decreased on administration of testosterone. Concentration of PAPS and activity of sulphate-activating system and sulphotransferase also decreased in the orchidectomized animals, and testosterone administration tended to restore this decrease to normal levels.
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PMID:Sex hormones and metabolism of glycosaminoglycans. I. Effect of orchidectomy and administration of testosterone in rabbits. 99 37

A series of pilot studies are presented utilizing mouse and human infections with M. leprae and mouse infections with M. lepraemurium relating to the previously reported finding that hyaluronic acid seems to be a major nutrient substrate for these bacilli. The "feeding" of hyaluronic acid to the bacilli enhanced the growth of M. leprae in mouse abdominal walls and increased the Morphologic Index of M. lepraemurium infection. Saccharic acid, an inhibitor of beta-glucuronidase previously reported as present in these leprosy bacilli, caused marked regression of advanced M. lepraemurium infection, inhii. Ascorbic acid (vitamin C), also an inhibitor of beta-glucuronidase, given at a level of 1.5 gm/day for 4.5 months to one lepromatous patient without other treatment and for up to 24 months to four other lepromatous patients receiving DDS, was accompanied by lesion regression and changes in bacillary morphology similar to those seen in the inhibitor treated mice. If these observations are confirmed the possible use of beta-glucuronidase inhibitors as a useful adjunct to other leprosy therapy is raised as is also the likelihood of developing new therapies.
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PMID:Acid mucopolysaccharide metabolism in leprosy. 3. Hyaluronic acid mycobacterial growth enhancement, and growth suppression by saccharic acid and vitamin C as inhibitors of beta-glucuronidase. 109 16

Previously, we isolated two mutants of Bacteroides thetaiotaomicron that were unable to grow on the mucopolysaccharide chondroitin sulfate (CS). One of these mutants (46-1) was outcompeted by the wild type in the intestinal tracts of germfree mice, whereas the other mutant (46-4) competed equally with the wild type. In the present article, we report a detailed characterization of these two mutants. Assays of enzymes in the CS utilization pathway revealed that 46-1 did not express one of these enzymes, chondro-6-sulfatase. The absence of chondro-6-sulfatase activity in extracts from 46-1 allowed us to detect a previously unknown activity of another enzyme in the CS breakdown pathway, beta-glucuronidase. In addition to hydrolyzing its normal substrate (an unsulfated disaccharide), beta-glucuronidase also hydrolyzed the 6-sulfated disaccharide subunit of CS. Two-dimensional gel analysis of polypeptides produced by 46-1 showed that several proteins other than the 6-sulfatase were either missing or expressed aberrantly. Thus, 46-1 could be a regulatory mutant. Mutant 46-4 was unable to grow on CS, hyaluronic acid, or disaccharides of CS. Thus, expression of the CS pathway enzymes could not be induced. Nonetheless, the growth pattern of 46-4 and some other findings indicate that the structural genes for these enzymes were still intact. The most likely target of mutant 46-4 is a regulatory locus that is required for expression of CS utilization genes. A surprising characteristic of 46-1 was its inability to grow on heparin, a mucopolysaccharide which is structurally similar to CS but is utilized by a different pathway.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Analysis of two chondroitin sulfate utilization mutants of Bacteroides thetaiotaomicron that differ in their abilities to compete with the wild type in the gastrointestinal tracts of germfree mice. 157 88


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