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)

We have studied the role of arachidonic acid (AA) metabolism in the release of lysosomal enzymes (beta-glucuronidase and lysozyme) from human polymorphonuclear leukocytes (PMNs). 5,8,11,14-Eicosatetraenoic acid (ETYA), which inhibits both the cyclo-oxygenase and the lipoxygenase pathways of AA metabolism, was found to cause a dose-dependent inhibition of lysosomal enzyme release from human PMNs induced by immunological (i.e., serum-treated zymosan: Zx) and nonimmunological stimuli (i.e., formyl methionine-containing peptide and the Ca2+ ionophore A23187). In contrast, the non-steroidal anti-inflammatory drugs (indomethacin, meclofenamic acid and aspirin), which only block the cyclo-oxygenase pathway of AA metabolism, had little effect on enzyme release from PMNs induced by the same stimuli. 5,8,11-Eicosatriynoic acid (ETI), a selective inhibitor of the lipoxygenase pathway of AA metabolism, caused a dose-dependent inhibition of lysosomal enzyme release elicited by Zx, f-met peptide, and A23187. p-Bromophenacyl bromide (BPB), which inhibits the phospholipase A2 (PLA2) activity in several tissues, was found to cause a dose-dependent inhibition of lysosomal enzyme release induced by the same immunological and non-immunological stimuli. The inhibitory effect of BPB on enzyme release was irreversible and extremely rapid. It appears that activation of PLA2 and the products of the AA metabolism, generated via a lipoxygenase pathway, play an essential role in the biochemical control of human PMNs activation and secretion.
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PMID:Possible role of arachidonic acid and of phospholipase A2 in the control of lysosomal enzyme release from human polymorphonuclear leukocytes. 664 91

In this study, an effect of single administration of organic thio-compounds on the combined use with uridine diphosphate glucuronic acid was investigated. In the single administration of organic thio-compounds to Wistar strain rats, the synthesis of glucuronide was slightly accelerated by glutathione or methionine, but it was not so much as in the single administration of UDPGA. The glucuronyltransferase activity was accelerated, when either taurine or methionine was administered in combination with UDPGA. None of these organic thio-compounds used in this study showed more significant inhibitory action of beta-glucuronidase activity than UDPGA in the single administration. It was perceived, however that the inhibitory action of beta-glucuronidase activity was much accelerated, when UDPGA was administered in combination either with taurine or methionine. In the administration of organic thio-compounds to Gunn strain rats, cysteine was detected to be the compound which accelerated the synthesis of glucuronide. It was also noted that no organic thio-compounds used in this study affected as influence on beta-glucuronidase activity.
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PMID:Effect of organic thio-compounds on detoxication of glucuronyltransferase and beta-glucuronidase in the rat liver. 679 Jul 25

Human red blood cell (RBC) membranes have been reported to contain both high and low affinity 'forms' of the drug metabolizing enzyme thiol methyltransferase (TMT). The biochemical characteristics of the two 'forms' of human RBC TMT were compared. Apparent Km constants of the high affinity activity for 2-mercaptoethanol and S-adenosyl-L-methionine, cosubstrates for the TMT reaction, were 0.38 mumol/l and 2.6 mumol/l, respectively. These constants may be compared with values of 20 mmol/l and 43 mumol/l, respectively, previously reported for the low affinity form of RBC TMT activity. The properties and regulation of the two forms of TMT were then compared with each other and also with those of two 'control' enzymes, phenol methyltransferase (PMT) and beta-glucuronidase. When high and low affinity TMT, PMT and beta-glucuronidase activities were measured in RBC membranes from 22 individual subjects, there were highly significant correlations among all three methyltransferase activities (all r values greater than 0.95), but beta-glucuronidase activity did not correlate significantly with any of the methyltransferase activities (all r values less than 0.40). The thermal stabilities of the three methyltransferases were very similar. They were all inactivated approximately 50% by incubation at 48 degrees C for 15 min. beta-Glucuronidase activity was approximately 50% inactivated by incubation at 76 degrees C for 15 min. PMT and both TMT activities had similar subcellular distributions and similar responses to ions and to enzyme inhibitors. These results suggested that high and low affinity TMT and PMT activities might be catalyzed by the same enzyme. Alternatively, these three RBC membrane methyltransferase activities might be regulated in a parallel fashion.
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PMID:Correlation of low and high affinity thiol methyltransferase and phenol methyltransferase activities in human erythrocyte membranes. 688 20

Two beta-glucuronidase-deficient Mennonite siblings were found to be homozygous for a mutation in exon 3 of the beta-glucuronidase gene that produces a Leu-->Phe substitution (L176F). The siblings also have the previously described benign polymorphism, P649L. Although their cultured fibroblasts contained 1.5-2.2% of normal beta-glucuronidase activity, transient expression of the L176F/P649L cDNA in COS cells produced nearly as much enzyme activity as the wild-type control cDNA. The L176F/P649L enzyme was as stable as wild-type enzyme following endocytosis by fibroblasts and delivery to lysosomes, but was more labile to heat inactivation at 65 degrees C. To study the mutant enzyme at lower levels of expression, we stably transfected mouse mucopolysaccharidosis type VII cells with the L176F/P649L cDNA and selected single-copy cell lines. Metabolic labeling with [35S]methionine revealed that cell lines expressing the mutant enzyme activity at low levels (7-10% of the wild type) actually produced the same amount of enzyme protein as the cell lines expressing the more active wild-type enzyme. However, the cell lines expressing four times this much mutant enzyme protein produced 150-200% as much enzyme activity as the cell line expressing the single-copy wild-type cDNA. These data suggest that overexpression can drive the folding reaction or the self-association of mutant monomers to form active tetramers and, at least partially, correct the beta-glucuronidase deficiency seen at low levels of expression with certain missense mutations.
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PMID:Overexpression rescues the mutant phenotype of L176F mutation causing beta-glucuronidase deficiency mucopolysaccharidosis in two Mennonite siblings. 808 38

The mitochondrial F1-ATPase beta subunit (ATPase-beta) of Nicotiana plumbaginifolia is nucleus-encoded as a precursor containing an NH2-terminal extension. By sequencing the mature N. tabacum ATPase-beta, we determined the length of the presequence, viz. 54 residues. To define the essential regions of this presequence, we produced a series of 3' deletions in the sequence coding for the 90 NH2-terminal residues of ATPase-beta. The truncated sequences were fused with the chloramphenicol acetyl transferase (cat) and beta-glucuronidase (gus) genes and introduced into tobacco plants. From the observed distribution of CAT and GUS activity in the plant cells, we conclude that the first 23 amino-acid residues of ATPase-beta remain capable of specifically targeting reporter proteins into mitochondria. Immunodetection in transgenic plants and in vitro import experiments with various CAT fusion proteins show that the precursors are processed at the expected cleavage site but also at a cryptic site located in the linker region between the presequence and the first methionine of native CAT.
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PMID:Truncated presequences of mitochondrial F1-ATPase beta subunit from Nicotiana plumbaginifolia transport CAT and GUS proteins into mitochondria of transgenic tobacco. 815 82

Quercetin is highly mutagenic in vitro, yet is not carcinogenic when administered chronically at large doses to rodents for 12 months. We hypothesized that catechol-O-methyltransferase-catalyzed O-methylation of quercetin and other mutagenic catechol-containing flavonoids may provide an efficient inactivation in vivo and may therefore prevent tumor induction by these flavonoids. After one intraperitoneal administration of 50 mg/kg quercetin to hamsters, a urinary ether extract contained 2% quercetin and 97% 3'-O-methylquercetin. When the urine was treated first with beta-glucuronidase and sulfatase, 13% quercetin and 87% 3'-O-methylquercetin were recovered. Quercetin was rapidly O-methylated by either porcine liver or hamster kidney catechol-O-methyltransferase, with Km values of 6.1 and 6.9 microM and Vmax values of 14,870 and 200 pmol/mg of protein/min, respectively. S-Adenosyl-L-homocysteine exhibited a potent feedback inhibition of the catechol-O-methyltransferase-catalyzed O-methylation of quercetin by a competitive mechanism with respect to S-adenosyl-L-methionine and by a competitive plus noncompetitive mechanism with respect to the substrate. A comparison of the O-methylation rates and kinetic characteristics (Km, Vmax, and Vmax/Km) demonstrated that rates of O-methylation of quercetin and fisetin were up to three orders of magnitude higher than those of catechol estrogens and catecholamines. In conclusion, the rapid metabolic inactivation of mutagenic flavonoids catalyzed by catechol-O-methyltransferase may be a major reason for the lack of their carcinogenic activities in vivo.
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PMID:Catechol-O-methyltransferase-catalyzed rapid O-methylation of mutagenic flavonoids. Metabolic inactivation as a possible reason for their lack of carcinogenicity in vivo. 827 10

Sertoli cells were isolated from prepubertal mice and cultured in serum-free medium to determine whether they secrete glycoproteins containing mannose 6-phosphate (M6P). Assays of the conditioned medium for lysosomal enzyme precursors, which typically bear the M6P recognition marker, indicated that Sertoli cells selectively secreted beta-N-acetylhexosaminidase and alpha-mannosidase, but not beta-glucuronidase or beta-galactosidase. Sertoli cells were labeled metabolically with [35S]methionine and the conditioned medium was fractionated on a cation-independent M6P receptor affinity column. Most of the secreted proteins did not bind to the column (peak A); however, approximately 10% of the radioactivity eluted as a low-affinity fraction (peak B), and 5-11% of the recovered cpm bound to the column and were eluted with 2.5 mM M6P (peak C). The radiolabeled proteins in each fraction were analyzed by one- and two-dimensional electrophoresis and fluorography. Two protein bands with molecular weights of 30,000 and 35,000 were present in peak B. Peak C contained at least ten M6P-containing glycoproteins with molecular weights between 30,000 and 135,000 and isoelectric points < 6.5. The 35,000-molecular-weight constituent prominent both in peaks B and C was identified as procathepsin L by immunoprecipitation with a specific antibody. When pachytene spermatocytes and round spermatids were cultured overnight in the presence of peak C glycoproteins radiolabeled with 125I, both germ cell types accumulated these Sertoli M6P-glycoproteins by a receptor-mediated process that was specifically inhibited by M6P. The Sertoli M6P-glycoproteins taken up by germ cells were processed to lower molecular weight forms. These results provide evidence that M6P receptors on the surface of spermatogenic cells endocytose secrete glycoproteins that are likely to be present in the seminiferous epithelium.
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PMID:Mouse Sertoli cells secrete mannose 6-phosphate containing glycoproteins that are endocytosed by spermatogenic cells. 828 71

We have isolated and determined DNA sequence for the 5'-flanking regions of three Arabidopsis thaliana polyubiquitin genes, UBQ3, UBQ10, and UBQ11. Comparison to cDNA sequences revealed the presence of an intron in the 5'-untranslated region at the same position immediately upstream of the initiator methionine codon in each of the three genes. An intron at this position is also present in two sunflower and two maize polyubiquitin genes. An intron is also found in the 5'-untranslated regions of several animal polyubiquitin genes, although the exact intron position is not conserved among them, and none are in the same position as those in the higher plant polyubiquitin genes. Chimeric genes containing the 5'-flanking regions of UBQ3, UBQ10, and UBQ11 in front of the coding regions for the reporter enzyme Escherichia coli beta-glucuronidase (GUS) were constructed. When introduced transiently into Arabidopsis leaves via microprojectile bombardment, all resulted in readily detectable levels of GUS activity that were quantitatively similar. The introns of UBQ3 and UBQ10 in the corresponding promoter fragments were removed by replacement with flanking cDNA sequences and chimeric genes constructed. These constructs resulted in 2.5- to 3-fold lower levels of marker enzyme activity after transient introduction into Arabidopsis leaves. The UBQ10 promoter without the 5' intron placed upstream of firefly luciferase (LUX) resulted in an average of 3-fold lower LUX activity than from an equivalent construct with the UBQ10 intron. A UBQ3 promoter cassette was constructed for the constitutive expression of open reading frames in dicot plants and it produced readily detectable levels of GUS activity in transient assays.
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PMID:The intron of Arabidopsis thaliana polyubiquitin genes is conserved in location and is a quantitative determinant of chimeric gene expression. 838 9

Previous studies suggested that the first step in utilization of starch by Bacteroides thetaiotaomicron was binding of the polysaccharide to the cell surface, followed by translocation of the polysaccharide across the outer membrane into the periplasm. In this study, we report the molecular characterization of a gene that encodes an outer membrane protein that is essential for utilization of both maltooligosaccharides and starch. The gene, susC, encoded a protein of 115.3 kDa. Antibodies were raised against SusC, and the outer membrane location of SusC could be confirmed by Western blot (immunoblot) analysis. SusC had a possible signal sequence of between 20 and 39 amino acids, depending on which N-terminal methionine initiates the start of the protein. It also had some features typical of well-characterized outer membrane proteins from members of the family Enterobacteriaceae, such as a terminal phenylalanine residue and a region in the amino portion of the protein thought to be involved in stabilizing the protein in the outer membrane. The amino acid sequence, together with results of gene disruption experiments, suggested that SusC was not an amylolytic enzyme. Transcriptional fusion experiments, using beta-glucuronidase as a reporter group, showed that expression of susC was maltose regulated at the transcriptional level. This is the first molecular characterization of a B. thetaiotaomicron outer membrane protein involved in maltooligosaccharide and starch utilization.
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PMID:A Bacteroides thetaiotaomicron outer membrane protein that is essential for utilization of maltooligosaccharides and starch. 855 May 19

Patients with end-stage renal disease are acidotic and often develop secondary hyperparathyroidism. Whether acidosis contributes to the bone disease observed in these patients is not clear. To determine whether acidosis and parathyroid hormone (PTH) have additive effects on net calcium efflux (JCa+) from bone and on bone cell function, we measured JCa+, osteoblastic collagen synthesis, and osteoclastic beta-glucuronidase release from neonatal mouse calvariae cultured in control (Ctl, pH approximately 7.4) or acidified (Met, pH approximately 7.1) medium with or without a submaximal concentration of PTH (10(-10) M) for 48 h. Compared with Ctl, from 24 to 48 h JCa+ was increased with Met and with PTH, and the combination of Met + PTH increased JCa+ further. Compared with Ctl, collagen synthesis was decreased with Met and with PTH and decreased further with Met + PTH. There was an inverse correlation between percent collagen synthesis and JCa+. Compared with Ctl, beta-glucuronidase release into the medium was increased with Met and with PTH and increased further with Met + PTH. There was a direct correlation between medium beta-glucuronidase activity and JCa+. Osteoclastic beta-glucuronidase activity correlated inversely with osteoblastic collagen synthesis. During cultures to 96 h, there continued to be greater JCa+ from calvariae incubated with Met + PTH than from those with either treatment alone. Thus acidosis and PTH independently stimulated JCa+ from bone, inhibited osteoblastic collagen synthesis, and stimulated osteoclastic beta-glucuronidase secretion, whereas the combination had a greater effect on each of these parameters than either treatment alone. These findings indicate that acidosis and PTH can have an additive effect on bone cell function and suggest that uremic osteodystrophy may result from a combination of a low pH and an elevated PTH.
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PMID:Additive effects of acidosis and parathyroid hormone on mouse osteoblastic and osteoclastic function. 857 64


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