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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)
Mouse L cells that possess the cation-independent mannose 6-phosphate (Man 6-P)/insulin-like growth factor (IGF) II receptor change the extent to which they dephosphorylate endocytosed acid hydrolases in response to serum (Einstein, R., and C. A. Gabel. 1989. J. Cell Biol. 109:1037-1046). To investigate the mechanism by which dephosphorylation competence is regulated, the dephosphorylation of individual acid hydrolases was studied in Man 6-P/IGF II receptor-positive and -deficient cell lines. 125I-labeled Man 6-P-containing acid hydrolases were proteolytically processed but remained phosphorylated when endocytosed by receptor-positive L cells maintained in the absence of serum; after the addition of serum, however, the cell-associated hydrolases were dephosphorylated. Individual hydrolases were dephosphorylated at distinct rates and to different extents. In contrast, the same hydrolases were dephosphorylated equally and completely after entry into Man 6-P/IGF II receptor-positive Chinese hamster ovary (CHO) cells. The dephosphorylation competence of Man 6-P/IGF II receptor-deficient mouse J774 cells was more limited. beta-Glucuronidase produced by these cells underwent a limited dephosphorylation in transit to lysosomes such that diphosphorylated oligosaccharides were converted to monophosphorylated species. The overall quantity of phosphorylated oligosaccharides associated with the enzyme, however, did not decrease within the lysosomal compartment. Likewise,
beta-glucuronidase
was not dephosphorylated when introduced into J774 cells via Fc receptor-mediated endocytosis. The CHO and J774 cell lysosomes, therefore, display opposite extremes with respect to their capacity to dephosphorylate acid hydrolases; within CHO cell lysosomes acid hydrolases are rapidly and efficiently dephosphorylated, but within J774 cell lysosomes the same acid hydrolases remain phosphorylated. This difference in processing indicates that lysosomes themselves exist in a dephosphorylation-competent and -incompetent state. Man 6-P-bearing acid hydrolases endocytosed by the L+ cells in the absence of serum were not distributed uniformly throughout the lysosomal compartment. The change in the dephosphorylation competence of L cells in response to serum suggests, therefore, that these cells contain multiple populations of lysosomes that differ with respect to their content of a mannose 6-
phosphatase
, and that serum factors affect the distribution of hydrolases between the different compartments.
...
PMID:Cell- and ligand-specific dephosphorylation of acid hydrolases: evidence that the mannose 6-phosphatase is controlled by compartmentalization. 184 1
Evidence for gene dosage effect for
beta-glucuronidase
(GUSB) and phosphoserine phosphatase (
PSP
), whose genes are mapped on chromosome 7, was searched in a group of 13 patients with myeloproliferative disorders and acquired monosomy 7. The monosomy 7 was the sole anomaly in nine patients and was associated with other chromosome changes in four. A group of 19 patients with similar diseases but with normal karyotype or with anomalies not involving chromosome 7 served as control. beta-galactosidase and arylsulphatase A, whose genes are not on chromosome 7, were tested as control enzymes. We obtained evidence for a gene dosage effect for GUSB, but not for
PSP
. When all cases with monosomy 7 were compared with controls, no dosage effect was observed for
PSP
, but when this group was split into two, according to the presence of anomalies additional to the monosomy 7, the values of activity in the group with additional anomalies were significantly lower than in the controls. Thus, in the case of
PSP
, the loss of one allele is not followed immediately by reduction in activity, and this could be due to the specific importance of
PSP
in nucleic acid metabolism. We postulate that some regulatory mechanisms are able to keep normal levels of
PSP
even in the presence of only one allele, and that they are overwhelmed only when additional chromosome changes are present. These changes tend to involve chromosomes carrying genes for enzymes involved in a metabolic pathway closely related to
PSP
functions, and only then is a gene dosage effect for
PSP
detectable.
...
PMID:Gene dosage effect in acquired monosomy 7: distinct behaviour of beta-glucuronidase and phosphoserine phosphatase. 196 82
Inhibition of a tartrate-resistant acid phosphatase (ACP) from Leishmania donovani and the tartrate-sensitive ACP from human seminal fluid (prostatic ACP) was examined using a series of 13 molybdate-containing heteropolyanions. The heteropolyanions were divided into four groups based on the number of molybdenum atoms they contain: Group I, Mo4; Group II, Mo6-8; Group III, Mo12; Group IV, Mo18. Two of the four groups, those consisting of compounds that contain either an Mo4 unit or an Mo18 unit with a heteroatom in the central cavity, were potent inhibitors and exhibited the highest degree of selectivity against the leishmanial and seminal fluid ACPs. The inhibition of prostatic ACP by complex E2 could be completely reversed by dialysis. Little inhibition of the acid phosphatase,
beta-glucuronidase
, or alpha-mannosidase from human spleen was observed with complexes B' and E2. For the seminal fluid
phosphatase
, the Ki values obtained with arsenate and vanadate depended markedly on pH, suggesting that, unlike most other phosphatases, the conformation of the inhibitor binding site on human seminal fluid ACP is pH-dependent. Results of competition experiments performed with various inhibitor pairs indicated that complex D2 binds to the active site of prostatic ACP while complex M binds at some site on the enzyme that affects the active site. Binding of complex M also modifies the affinity of the enzyme for other inhibitors such as vanadate. The potency of several heteropolyanion complexes and their selective inhibition of pathophysiologically significant acid phosphatases indicate that these compounds may have value as tools for study of the structure and function of this class of enzyme and perhaps in the therapy of human disease.
...
PMID:Inhibition of human seminal fluid and Leishmania donovani phosphatases by molybdate heteropolyanions. 199 14
We studied the effect of adenosine nucleotides on several aspects of the functional activation of human peripheral blood polymorphonuclear leukocytes (PMN). Radiolabeled ATP bound to PMN in a manner suggesting the existence of specific binding sites because: 1) binding was reversed (92 +/- 6%) by 100-fold excess concentrations of unlabeled ATP but minimally by either ADP (43 +/- 12%) or GTP (37 +/- 8%); and 2) binding saturation was achieved (i.e., specific binding did not increase) above 250 microM ATP. Binding studies revealed that significant ATP hydrolysis occurred, even at low temperatures and in the presence of
phosphatase
inhibitors. Adenosine nucleotides activated signal transduction mechanisms in PMN because: 1) 1 to 100 microM ATP and 5'-adenylylimidodiphosphate (AMP-PNP) stimulated increased production of 1,2-diacylglycerols; 2) ATP (0.5 to 500 microM) and ADP (0.1 to 10 mM) induced increased insoluble protein kinase (PKC) activity in a dose-dependent manner when used at concentrations greater than 50 microM; 3) ATP (greater than or equal to 50 microM) induced a shift in the solubility of phorbol receptors from mostly soluble (89% in untreated cells) to mostly insoluble (68%), whereas ADP, GTP, and GDP were effective at higher concentrations; and 4) greater than or equal to 50 microM ATP stimulated increased phosphorylation of endogenous PMN proteins. AMP-PNP induced PKC activity and phosphoprotein changes that were qualitatively similar to those observed when PMN were treated with ATP, suggesting that extracellular ATP hydrolysis is not required for signal transduction to activate PKC. Functionally, ATP stimulated the secretion of specific (but not azurophil) granules because vitamin B12-binding protein and low levels of lysozyme, but not
beta-glucuronidase
, were released; qualitatively similar results were obtained by using AMP-PNP. These results suggest that certain adenosine nucleotides employed at physiologically relevant concentrations stimulate increased 1,2-diacylglycerol production, PKC activity, granule secretion, and endogenous phosphoprotein formation in a manner that is independent of extracellular ATP hydrolysis.
...
PMID:Extracellular adenosine nucleotides stimulate protein kinase C activity and human neutrophil activation. 215 72
In order to investigate the availability and release of enzymes from eosinophilic granulocytes in response to a variety of stimuli, guinea pig peritoneal eosinophils were obtained after repeated intraperitoneal injections of freeze-dried Trichinella spiralis larvae. The activities of the enzymes peroxidase, arylsulfatase B,
beta-glucuronidase
, aminopeptidase, histaminase, cytochrome c oxidase, acid phosphatase, adenosine triphosphatase and glucose 6-
phosphatase
, and the major basic protein (MBP) were studied histochemically and, in part, also biochemically. Eosinophils were incubated with the following substances: histamine, platelet activating factor, calcium ionophore, compound 48/80, leukotriene B4, prostaglandins E1, and E2, heparin, and eosinophil-chemotactic factors from neutrophils and lymphocytes. Eosinophils displayed a selective and stimulus-dependent enzyme and MBP reaction. Calcium ionophore and compound 48/80 provoked a release of cytotoxic major basic protein, partly associated with peroxidase release, while leukotriene B4 and eosinophil chemotactic factors caused histaminase and peroxidase release and activated leucinaminopeptidase. Heparin and calcium ionophore induced release of both MBP and histaminase. These data support the concept that eosinophils exhibit either inflammatory or cytotoxic, or antiinflammatory properties upon stimulation by various agents.
...
PMID:Activation and release of enzymes and major basic protein from guinea pig eosinophil granulocytes induced by different inflammatory stimuli and other substances. A histochemical, biochemical, and electron microscopic study. 275 82
In the context of studies bearing on the enzymatic activity in healthy veins and varicose veins, sample sections of veins were excised in eight patients with primary varices of the long saphenous vein. The veins were subjected to histochemical methods for identifying enzymes. The histochemical dosage related to lactate-dehydrogenase, alkaline phosphatase, adenosine triphosphoric acid enzymes, as well as lysosomal
beta-glucuronidase
, non-specific esterase and
phosphatase
acid enzymes. The authors deal with the specific problems involved in the different enzymatic methods, and their relevance to prognosis. In conformity with the results of our histochemical studies, the comparison between the enzymatic profiles of healthy and varicose veins showed an increase in lysosmal enzyme activity in the vein walls leading to varicose degeneration. The increase in activity was more pronounced in the media than in the intima. A reverse pattern was observed in the behaviour of enzymes involved in energetic metabolism. The enzymatic activity in the venous wall leading to varicose degeneration proved to have decreased. This reduction in the enzymatic activity was more marked in the intima than in the media and was particularly pronounced in the case of the histochemical identification of adenosine triphosphoric acid Ca++.
...
PMID:[Histochemical comparison of the enzyme profiles of healthy veins and varicose veins]. 356 64
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
To determine the localization of several enzymes in Tritrichomonas foetus, the axenic KV-1 strain was grown in Diamond's medium with bovine serum, homogenized in 0.25 M sucrose, and subjected to analytical differential and isopycnic centrifugation. The fractions were assayed for their enzymatic composition and examined electron microscopically. NADH and NADPH dehydrogenases, about 90% of the catalase, and two hydrolases, alpha-galactosidase and manganese-activated beta-galactosidase I are in the nonsedimentable part of the cytoplasm. alpha-Glycerophosphate and malate dehydrogenases are associated with a large particle, whose equilibrium density in sucrose gradients is 1.24. This particle corresponds to that population of the paracostal and paraxostylar granules which, having a uniform granular matrix surrounded by a single membrane, resemble microbodies from other organisms. The small sedimentable portion of catalase (about 10% of the total activity) is not associated with these granules and equilibrates at density 1.22. The nature of the subcellular entity carrying catalase could not be ascertained. Hydrolases with a pH optimum around 6-6.5 (protease, beta-N-acetylglucosaminidase, beta-N-acetylgalactosaminidase, and cation-independent beta-galactosidase II), as well as a large part of acid phosphatase, are associated with a population of large particles which equilibrate at densities from 1.15 to 1.20. The hydrolases in these granules lose their structure-bound latency easily after freezing and thawing. These particles correspond to another population of the paracostal and paraxostylar granules which have varied shape and inhomogeneous content with frequent myelin figures, indicating a digestive function. The rest of the
phosphatase
and most of the acid
beta-glucuronidase
activity are in a smaller granule fraction with an equilibrium density around 1.18. The latency of these enzymes is quite resistant to freezing and thawing. This particle population consists of smaller, very often flattened vesicles and granules, many of which are clearly fragments of the prominent Golgi apparatus of the cell.
...
PMID:Biochemical cytology of trichomonad flagellates. I. Subcellular localization of hydrolases, dehydrogenases, and catalase in Tritrichomonas foetus. 414 6
The series introduced by this paper reports the results of a detailed analysis of the microsomal fraction from rat liver by density gradient centrifugation. The biochemical methods used throughout this work for the determination of monoamine oxidase, NADH cytochrome c reductase, NADPH cytochrome c reductase, cytochrome oxidase, catalase, aminopyrine demethylase, cytochromes b(5) and P 450, glucuronyltransferase, galactosyltransferase, esterase, alkaline and acid phosphatases, 5'-nucleotidase, glucose 6-
phosphatase
, alkaline phosphodiesterase I, N-acetyl-beta-glucosaminidase,
beta-glucuronidase
, nucleoside diphosphatase, aldolase, fumarase, glutamine synthetase, protein, phospholipid, cholesterol, and RNA are described and justified when necessary.
...
PMID:Analytical study of microsomes and isolated subcellular membranes from rat liver. I. Biochemical methods. 415 Apr 88
Rat liver microsomal fractions have been equilibrated in various types of linear density gradients. 15 fractions were collected and assayed for 27 constituents. As a result of this analysis microsomal constituents have been classified, in the order of increasing median density, into four groups labeled a, b, c, and d. Group a includes: monoamine oxidase, galactosyltransferase, 5'-nucleotidase, alkaline phosphodiesterase I, alkaline phosphatase, and cholesterol; group b: NADH cytochrome c reductase, NADPH cytochrome c reductase, aminopyrine demethylase, cytochrome b(5), and cytochrome P 450; group c: glucose 6-
phosphatase
, nucleoside diphosphatase, esterase,
beta-glucuronidase
, and glucuronyltransferase; group d: RNA, membrane-bound ribosomes, and some enzymes probably adsorbed on ribosomes: fumarase, aldolase, and glutamine synthetase. Analysis of the microsomal fraction by differential centrifugation in density gradient has further dissociated group a into constituents which sediment more slowly (monoamine oxidase and galactosyltransferase) than those of groups b and c, and 5'-nucleotidase, alkaline phosphodiesterase I, alkaline phosphatase, and the bulk of cholesterol which sediment more rapidly (group a2). The microsomal monoamine oxidase is attributed, at least partially, to detached fragments of external mitochondrial membrane. Galactosyltransferase belongs to the Golgi complex. Group a2 constituents are related to plasma membranes. Constituents of groups b and c and RNA belong to microsomal vesicles derived from the endoplasmic reticulum. These latter exhibit a noticeable biochemical heterogeneity and represent at the most 80% of microsomal protein, the rest being accounted for by particles bearing the constituents of groups a and some contaminating mitochondria, lysosomes, and peroxisomes. Attention is called to the operational meaning of microsomal subfractions and to their cytological complexity.
...
PMID:Analytical study of microsomes and isolated subcellular membranes from rat liver. 3. Subfractionation of the microsomal fraction by isopycnic and differential centrifugation in density gradients. 415 Apr 90
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