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PubMed1975

Egasyn, a protein complexed with microsomal beta-glucuronidase.

Two polypeptide chains are present in murine beta-glucuronidase precipitated with a specific anti-beta-glucuronidase antibody F(ab)2 fragment. One is the catalytic subunit of beta-glucuronidase and the other has the properties predicted for the hypothetical beta-gluronidase membrane anchor protein. The new protein, named egasyn, is associated with microsomal, but no lysosomal beta-glucuronidase. It is released from the microsomal beta-glucuronidase complex by heat treatment. The YBR strain of mice carrying the Eg degrees mutation does not form an egasyn-beta-glucuronidase complex and is unable to retain beta-glucuronidase on microsomal membranes.

Animals↗
PubMed1976

Beta-glucuronidase isozyme patterns of experimental hepatomas of rats.

Beta-Glucuronidase isozymes in rat tissues were separated by electrophoresis on cellulose acetate membranes. Using this method, beta-glucuronidase isozyme patterns were studied in normal rat liver and experimental hepatomas with different growth rates. Changes of isozyme patterns during postnatal development were also studied in rat liver. Normal rat liver contained six types of beta-glucuronidase, numbered I to VI in order to decreasing mobility to the cathode. Type II beta-glucuronidase stained most intensely and was detected in all the cells examined. The isozyme patterns of Morris hepatomas, which are slowly growing and not highly deviated, resembled that of normal rat liver but lacked definite Type III beta-glucuronidase. Yoshida ascites hepatomas, which are rapidly growing and highly deviated, contained only Type II, but some had Types II, V, and VI beta-glucuronidase. Embryonal liver just before birth contained only Type II, but with increase in activity during development after birth, minor bands of Type I and Types III to VI beta-glucuronidase appeared successively to complete the adult pattern.

Animals↗
PubMed1990

The occurrence of beta-glucuronidase in erythrocyte inclusions.

This study presents erythrocytic inclusion bodies exhibiting histochemically a strong beta-glucuronidase activity. The unique occurrence of this enzyme in cells of the erythropoietic series has never been described before and characterizes a novel type of erythrocyte inclusions mainly observed in patients suffering from liver damage but also from myelodysplasia and congenital dyserythropoietic anemia type I. Since it is known that hepatocytes contain high activities of beta-glucuronidase, we supposed a relationship between an increased breakdown of liver cells and the appearance of beta-glucuronidase positive inclusions in the red cells. To prove this hypothesis, we determined the beta-glucuronidase plasma levels of 99 unselected patients suffering from various liver disorders in comparison with 19 healthy controls by use of the umbelliferone technique. Our results indicate that in cases with liver diseases beta-glucuronidase plasma levels are significantly increased as compared with normal persons. The availability of a sufficient amount of beta-glucuronidase, thus, seems to be one prerequisite for the appearance of these inclusions in erythrocytes. As demonstrated by our investigations on congenital dyserythropoietic anemia, in which the red cells also show beta-glucuronidase positive inclusions, another premise seems to be an elevated autophagolysosomal activity in the erythrocytes.

Adult↗
PubMed1987

An accessory protein identical to mouse egasyn is complexed with rat microsomal beta-glucuronidase and is identical to rat esterase-3.

We report biochemical, immunological, and genetic studies which demonstrate that an accessory protein with the essential features of mouse egasyn is complexed with and stabilizes a portion of beta-glucuronidase in microsomes of rat liver. The accessory protein exists as a complex with beta-glucuronidase since it coprecipitates with beta-glucuronidase after treatment of extracts with a specific beta-glucuronidase antibody. The two proteins are associated by noncovalent bonds since they are easily dissociated at elevated temperatures. Only 20-25% of total liver accessory protein is complexed with microsomal beta-glucuronidase. The remainder exists as a free form. The molecular weight of the accessory protein is 61 to 63 kDa depending upon the rat strain of origin. This protein, like mouse egasyn, has esterase catalytic activity and is concentrated in microsomes. The accessory protein is genetically polymorphic with at least four alleles. Combined biochemical and genetic evidence indicates it is identical with esterase-3 of the rat. Also, both mouse egasyn and rat esterase-3 react with antisera to egasyn and to rat esterase-3, indicating they are homologous proteins. Several inbred rat strains lack microsomal beta-glucuronidase. The same strains lack the accessory protein, suggesting that stabilization of beta-glucuronidase in rat microsomes requires egasyn.

Alleles↗
PubMed1984

Beta-glucuronidases of clostridium perfringens.

GAM broth was cultured for 5 days at 37 degrees C to obtain maximum yields of extracellular beta-glucuronidase from smooth colonies of Clostridium perfringens (Hobbs' type 4) isolated from the feces of a patient. A crude enzyme preparation was obtained by 20-80% ammonium sulfate precipitation of the broth. The beta-glucuronidase was purified using DEAE cellulose column chromatography, gel filtration on Sephadex G-200, and affinity chromatography on Sepharose 4B-bound glucuronolactone. We obtained two kinds of beta-glucuronidase. Properties of the purified beta-glucuronidase I were an optimum pH of 7.2, a pH stability range below 7.0, and a molecular weight of 115,000. The purified beta-glucuronidase II had an optimum pH of 6.0, pH stability at around 6.0, and a molecular weight of 195,000. Cu++ and Hg++ were strong inhibitors, which inhibition was restored by cysteine. EDTA did not influence enzyme activity. The Michaelis constants of beta-glucuronidase I and beta-glucuronidase II for p-nitrophenyl glucuronide were 1.25 X 10(-3) M and 4.17 X 10(-4) M, for naphthol AS-BI glucuronide 1.35 X 10(-4) M and 1.14 X 10(-4) M, and for phenolphthalein glucuronide 7.46 X 10(-5) M and 2.50 X 10(-4) M.

Clostridium perfringens↗
PubMed1984

Role of urinary beta-glucuronidase in human bladder cancer.

It has been suggested that high levels of urinary beta-glucuronidase may increase an individual's risk of bladder cancer by releasing free carcinogens from their inactive glucuronide conjugates in the bladder. The hypothesis derives in part from the high levels of urinary beta-glucuronidase observed in bladder cancer patients. Because most of the individual variation in levels of urinary beta-glucuronidase and other lysosomal enzymes in the normal population is genetically determined, we would expect that, if high glucuronidase levels were a predisposing factor in the disease, bladder cancer patients would transmit this trait to their progeny. We have tested this hypothesis and find that levels of urinary beta-glucuronidase and three other lysosomal enzymes, alpha-galactosidase, beta-galactosidase, and beta-hexosaminidase, are not significantly elevated in 34 progeny of bladder cancer patients compared to 34 matched controls. Additionally, 15 bladder cancer patients judged to be disease free for a median time of 5 years did not have elevated levels of urinary beta-glucuronidase when compared to a normal population of 125 individuals. Thus, the high levels of glucuronidase observed in bladder cancer patients are most likely a consequence of disease rather than a cause.

Adult↗
PubMed1978

Turnover of murine beta-glucuronidase. Comparison among liver, kidney, and spleen and between lysosomes and microsomes.

The turnover properties of murine beta-glucuronidase in several tissues and at two subcellular sites have been determined by monitoring the radioactivity present in immunoprecipitated enzyme at a number of time points following the in vivo administration of a single radiolabeled protein precursor (either L-[3,4(-3H)]leucine or or NaH14CO3). In all experiments a considerable period of time was required for the attainment of maximum specific radioactivity in glucuronidase. Similar labeling kinetics was found when [3H]leucine incorporation was monitored in immunoprecipitated murine liver delta-aminolevulinate dehydratase. Half-life estimates of 2 to 3 days were obtained for glucuronidases of liver, kidney, and spleen. In most strains of inbred mice, it is known that approximately 60% of total liver glucuronidase activity resides in lysosomes, while 40% is within the membranes of the endoplasmic reticulum (Ganschow, R. E. and Paigen, K. (1968) Genetics 59, 335-349). These two subcellular forms of glucuronidase turn over at similar rates. Furthermore, the bulk of glucuronidase in the endoplasmic reticulum does not serve as precursor to lysosomal glucuronidase.

Animals↗
PubMed1993

Deconjugation of bilirubin-IX alpha glucuronides: a physiologic role of hepatic microsomal beta-glucuronidase.

beta-Glucuronidase is an acid hydrolase located in both the lysosomal and microsomal compartments of the hepatocyte. The function of the latter remains undefined. We postulated that microsomal beta-glucuronidase may be responsible for the deconjugation of bilirubin-IX alpha glucuronides which are synthesized primarily in the hepatic microsomal compartment. We utilized two unique congenic strains of mice to characterize the role of hepatic beta-glucuronidase in the metabolism and disposition of bilirubin-IX alpha; the first exhibited less than 1% of total hepatic beta-glucuronidase activity (ATM), the second lacked only the microsomal enzyme activity (AT1). The biliary excretion of bilirubin-IX alpha conjugates was quantitated using reverse-phase high performance liquid chromatography. Under basal conditions, there was a 2-fold increase in the biliary excretion of bilirubin-IX alpha monoglucuronides and total glucuronides in the AT1 and ATM mutants compared to the normal controls. When the plasma bilirubin-IX alpha level was increased to approximately 7 mg/dl to simulate hyperbilirubinemia, by intravenous administration of [14C]bilirubin-IX alpha, mathematical modeling of the biliary excretion curves of bilirubin-IX alpha glucuronides revealed qualitative differences between control and mutant animals, whereas both mutant groups were similar. Collectively, these data demonstrate that microsomal beta-glucuronidase modulates the net rate of bilirubin-IX alpha glucuronidation and glucuronide excretion in bile, under both basal and hyperbilirubinemic conditions, and that lysosomal beta-glucuronidase has no such effects. Hepatic microsomal beta-glucuronidase appears likely to influence the biliary excretion and hence the hepatic elimination of endogenous and xenobiotic substrates (e.g. carcinogens) which undergo hepatic glucuronidation.

Animals↗
PubMedDate not supplied

Androgen regulation of molecular forms of beta-D-glucuronidase in the mouse epididymis: comparison with liver and kidney.

The expression and androgen regulation of beta-glucuronidase molecular forms were examined in mouse epididymis, liver, and kidney. Two-dimensional polyacrylamide gel electrophoresis performed under nondenaturing conditions showed that, compared to liver and kidney, which contain four microsomal (M1-M4) and a major lysosomal (L) form of beta-glucuronidase, the epididymis revealed regional differences and tissue specificity in the expression of the various molecular forms of the enzyme. Only the lysosomal form (pI 5.4-6.1) is present in the caput epididymidis while the corpus/cauda contains the lysosomal form, the free X form (pI 5.9-6.3) and the four microsomal forms (X form complexed with egasyn). Mutant mice that lack egasyn have no microsomal forms in the distal epididymis. In epididymal fluid, the lysosomal form is found throughout the epididymis, whereas the X form appears only in the corpus/cauda epididymidis. Sodium dodecyl Sulfate (SDS)-gel electrophoresis and western blot analysis of immunoprecipitated beta-glucuronidase revealed only one band corresponding to the L form (apparent molecular weight 74 kDa) in the caput epididymidis and two bands in the corpus/cauda (apparent molecular weights 73 and 75 kDa), corresponding to L and X forms, respectively. Castration of mice led to the suppression of the regional differences in the appearance of X and M forms in the epididymis. Testosterone supplementation to castrated mice restored the characteristic electrophoretic pattern of beta-glucuronidase in the caput epididymidis. In the liver and kidney, castration has no effect on the expression of the molecular forms, whereas androgen treatment induced the X form in the kidney. Histochemical localization of beta-glucuronidase confirmed the region specificity seen in the epididymis and in addition revealed cell specificity in the expression of beta-glucuronidase. These results indicate that beta-glucuronidase shows tissue specificity and, in the case of the epididymis, region and cell specificity. In addition, the enzyme in the different tissues responds differentially to androgens.

Animals↗
PubMed1986

[Studies on beta-glucuronidase activities in liver, stomach and small intestinal tissues of rabbits infected with Clonorchis sinensis]

The author has studied the beta-glucuronidase activity in several tissues such as liver, stomach and small intestine of the male and female rabbits infected with different doses of metacercariae of Clonorchis sinensis. The metacercariae of Clonorchis sinensis were isolated from Pseudorasbora parva caught in Kim Hae by digestion technic. The experimental animals were sacrificed in the period of 1, 7, 14, 21, 28 and 35th days following the infection. The results obtained were summarized as follows: In the groups infected with 100 metacercariae, beta-glucuronidase activity was slightly increased during the entire periods than control rabbits. It was the highest in the first day with 1.535 and 1.421 mu/g, 14th days with 2.521 and 2.200 mu/g, and then lowered by the time, gradually. In the groups infected with 500 metacercariae, beta-glucuronidase activity was highly increased on the first day with 1.535 and 1.866 mu/g than that 100 metacercariae groups according to each organs. It was the highest on the 7th day and 14th day. In the groups infected with 1,000 metacercariae, beta-glucuronidase activity was remarkably increased in the first and 14th days according to each organs, and then lowered gradually day by day. beta-glucuronidase activity of all organs was more increased than that of normal organs and the highest activity in the liver with 2.521 mu/g, intestine(1.612) and stomach (1.581) respectively. beta-glucuronidase activity of rabbits was higher in the female than in the male. On the basis of these results, it was suggested that beta-glucuronidase activity was affected by the duration of infection and by the number of Clonorchis sinensis, according to the organs and sex of the rabbits.

Journal Article↗
PubMed1989

D-glucaro-1,4-lactone: its excretion in the bile and urine and effect on the biliary secretion of beta-glucuronidase after oral administration in rats.

This experiment was designed to test the hypothesis that orally administered D-glucaro-1,4-lactone might be excreted in the bile and thus suppress the activity of biliary beta-glucuronidase, which is believed to play a key role in the development of pigment gallstones. D-Glucaro-1,4-lactone, 50 to 2,600 mu moles, was fed to adult Sprague-Dawley rats which had a bile fistula and were kept in metabolic cages for bile and urine collection. A total of 21 feeding experiments were carried out. Quantitation of D-glucaro-1,4-lactone and total D-glucaric acid as the sum of D-glucaric acid and its lactones in the bile and urine involved extraction of bile with tetrahexylammonium chloride, adjustment of pH, boiling and determination of percentage inhibition of beta-glucuronidase activity. The maximal velocity of beta-glucuronidase in the bile was also determined by the enzyme kinetic method. The results showed that 11% of administered D-glucaro-1,4-lactone was excreted in the urine and only 0.2% in the bile, with D-glucaro-1,4-lactone accounting for 20% of the total excreted D-glucaric acid. The concentration and excretory rate of total D-glucaric acid and D-glucaro-1,4-lactone in the urine, but not in the bile, were proportional to the amount of D-glucaro-1,4-lactone fed. The mean concentration of D-glucaro-1,4-lactone in the bile after feeding was 0.06 mM, which was capable of suppression of 75% of beta-glucuronidase activity. Oral administration of D-glucaro-1,4-lactone decreased biliary beta-glucuronidase concentration, slowed bile flow rate and hence decreased biliary beta-glucuronidase secretion.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Oral↗
PubMed1978

Segregation of genetic determinants for murine glucuronidase synthesis and loss in CXB recombinant-inbred strains.

A set of recombinant-inbred strains developed from mouse strains BALB/c and C57BL/6 includes two beta-glucuronidase phenotypes that are not seen in either of the progenitor strains. These new recombinant phenotypes indicate that glucuronidase levels are regulated by genes additional to the Gur locus, which is closely linked to the glucuronidase structural gene (Gus) and is known to regulate the rate of glucuronidase synthesis. In this study, induced rates of glucuronidase synthesis were determined for these recombinant-inbred strains, and rate constants for enzyme loss were calculated. The rate of synthesis was found to segregate with the Gus gene in all of the strains, and only the determinants for rate of enzyme loss recombined to give new phenotypes. It was concluded that at least two genes affect the rate of enzyme loss, that these genes are not closely linked to each other or to the Gur-Gus region on chromosome 5, and that no major determinants of glucuronidase synthesis segregate independently of Gur.

Animals↗
PubMed1983

[Experimental gallstone formation. Etiological significance of beta-glucuronidase producing bacteria and biliary obstruction].

Bile pigment gallstones were produced in six of six mongrel dogs by narrowing the cystic duct with ligature after a postoperative interval of seven days. beta-Glucuronidase producing group G Streptococcus and Staphylococcus aureus were found in the bile, the gallbladder wall, and the liver. In another trial similar gallstones were produced in four of eight dogs after mere injection of beta-glucuronidase producing Escherichia coli into the spleen resp. in six of eight dogs after injection of E. coli into the colon without ligature of the cystic duct. In an additional series gallstones were produced in six dogs after injection of beta-glucuronidase producing E. coli into the colon plus ligature of the cystic duct. The injected strain of E. coli was found in the bile, the gallbladder wall, the liver, and even within the produced gallstones. In a control group in none of six dogs gallstones were present. beta-Glucuronidase producing group G Streptococcus was found in the gallbladder of one dog, Pseudomonas aeruginosa was found in the gallbladder of another dog and Staphylococcus aureus in the liver and gallbladder wall of a third dog. We conclude from our experiments that merely bacterial infection of the biliary tract can lead to gallstone formation. The bacterial colonization of the liver and the biliary tract is promoted by biliary tract obstruction. beta-Glucuronidase producing bacteria increase the amount of beta-glucuronidase in the bile thus leading to calcium bilirubinate precipitation and gallstone formation by deconjugation of bilirubindiglucuronide.

Animals↗
PubMed1998

Interference by carbohydrate substrates, flavonoids, and monosaccharide derivatives on bacterial beta-D-glucuronidase assays.

Most commercially available test kits for water and foodstuffs use beta-galactosidase activity for coliforms and beta-glucuronidase activity for Escherichia coli. We tested the effects on the beta-glucuronidase activity of E. coli W3110 of substances usually present in foods and several synthetic pharmaceutical compounds. Thirteen substances were tested: three carbohydrates, four flavonoids, five monosaccharide derivatives, and dimethyl sulphoxide. In a minimum medium without any other carbon source, glucose (0.1 mM), quercetin (0.1 mM), silymarin (10 mg/L), D-gluconic acid (0.01 mM), D-gluconic acid lactone (0.01 mM), isopropyl-beta-D-thiogalacto pyranoside (1 mM), p-nitrophenyl beta-D-glucuronide (1 mM), and DMSO (1 M) completely inhibited E. coli glucuronidase activity at the above concentrations. However, the following compounds stimulated E. coli glucuronidase activity within the ranges of concentrations shown: glucose (0.0001-0.01 mM), lactose and sucrose (>0.1 mM), D-saccharic acid 1,4 lactone (0.0001-0.1 mM), p-nitrophenyl beta-D-glucuronide (0.001-0.01 mM) and DMSO (2-500 mM). In a rich culture medium that contained other carbon sources (lauryl tryptose broth) E. coli glucuronidase activity in the presence of the extra nutrients was unaffected by the test substances and therefore, under normal conditions in water or foods, they should not interfere with E. coli assays based on measurements of beta-glucuronidase activity.

Biological Assay↗
PubMed1983

Inhibition of polyamine synthesis blocks urinary secretion of beta-glucuronidase from mouse kidney.

The effect of inhibition of polyamine synthesis on castrated male mouse kidney beta-glucuronidase induction and secretion by testosterone was studied. Inhibition of the activities of polyamine synthesis key-enzymes, L-ornithine and S-adenosyl-L-methionine decarboxylases, was performed with the combined treatment of 2-difluoromethylornithine and methylglyoxal' bis(guanylhydrazone). Blockage of polyamine synthesis did not affect testosterone-induced increase in renal beta-glucuronidase but blocked its secretion into the urine. After withdrawal of inhibitor-treatment beta-glucuronidase secretion normalized, and repeated testosterone administration produced undisturbed beta-glucuronidase secretion peak in urine suggesting that blockage of beta-glucuronidase secretion was not due to the tissue damage produced by inhibitors. These results indicate that the stimulation of renal polyamine synthesis by testosterone is not necessary for the induction of beta-glucuronidase but is required for the urinary secretion of this protein.

Animals↗
PubMed1987

Involvement of the esterase active site of egasyn in compartmentalization of beta-glucuronidase within the endoplasmic reticulum.

Organophosphorous compounds, which are potent inhibitors of egasyn-esterase activity, caused a rapid dissociation of the high molecular weight egasyn-microsomal beta-glucuronidase complex when administered in vivo or when added in vitro to microsomal suspensions. The dissociation was relatively specific to phosphodiester inhibitors of the esterase active site. Also, the egasyn-esterase active site was inaccessible to substrates and to inhibitors when egasyn was complexed to beta-glucuronidase. Dissociation of the egasyn-microsomal beta-glucuronidase complex in vivo by organophosphorous compounds was followed by massive and rapid secretion of microsomal beta-glucuronidase, but not egasyn, into plasma. These experiments implicate the egasyn-esterase active site in attachment of microsomal beta-glucuronidase to egasyn by a novel mechanism that, in turn, compartmentalizes beta-glucuronidase within the endoplasmic reticulum.

Animals↗
PubMed1995

Arachidonate and other fatty acids mobilize Ca2+ ions and stimulate beta-glucuronidase release in a Ca(2+)-dependent fashion from undifferentiated HL-60 cells.

Arachidonate (1-300 microM) mobilized Ca2+ ions from an intracellular store and stimulated the entry of Ca2+ ions from the extracellular fluid in undifferentiated HL-60 cells that had been loaded with Fura-2. The integrated response was biphasic in form: arachidonate liberated Ca2+ ions from the intracellular store first, resulting in a transient increase in cytosolic free Ca2+ concentration ([Ca2+]i). Ca2+ entry from the extracellular fluid was not evident for a further 1-2 min. At baseline, [Ca2+]i was 48.1 +/- 14.0 nM (SEM, n = 5). Upon addition of arachidonate (100 microM), [Ca2+]i rose to a transient peak level of 217 +/- 38.6 nM (SEM, n = 5) and a later plateau level of 427 +/- 118 nM (SEM, n = 5). Removal of added Ca2+ ions from the extracellular fluid in the presence of EGTA (1.0 mM) had no effect on the initial transient response but abolished the second phase of the response. In HL-60 cells that had been loaded with BAPTA/AM, the initial transient phase of the response was abolished but the elevation in [Ca2+]i due to Ca2+ entry from the extracellular fluid was unaffected. Undifferentiated HL-60 cells also responded to arachidonate (100 microM) with an increase in the release of the lysosomal enzyme beta-glucuronidase. Arachidonate-induced beta-glucuronidase release from BAPTA-loaded cells or in control cells exposed to Ca(2+)-free solutions was inhibited by about 50%. In BAPTA-loaded cells that were incubated with Ca(2+)-free solutions, arachidonate-induced beta-glucuronidase release was inhibited by about 90%. Leukotriene B4 failed to elevate [Ca2+]i in the concentration range 0.01-1 microM and failed to activate beta-glucuronidase release in concentrations up to 10 microM. Furthermore, the cyclo-oxygenase/lipoxygenase inhibitor ETYA (100 microM) was without effect on secretion. Consistent with this finding, we found that a large number of unsaturated fatty acids could reproduce the effect of arachidonate on [Ca2+]i and beta-glucuronidase release. Fatty acids belonging to the omega-3, omega-6 and omega-7 unsaturated fatty acid families were effective in elevating [Ca2+]i and stimulating beta-glucuronidase release. However, three unsaturated fatty acids, all belonging to the omega-9 fatty acid family, were ineffective.

Arachidonic Acid↗
PubMed1995

A fluorometric beta-glucuronidase assay for analysis of bacterial growth in milk.

The growth of common mastitis-causing bacteria in milk was followed by a fluorometric technique based on the release of fluorescent 4-methylumbelliferone (4-MU) from 4-methylumbelliferyl-beta-D-glucuronide by the beta-glucuronidase of bacterial or milk origin. Three of four Escherichia coli strains, all four strains of Streptococcus uberis (4/4) and Streptococcus agalactiae (4/4) produced beta-glucuronidase. Four Staphylococcus aureus strains (4/4) and one E. coli strain, though unable to produce the enzyme, activated the milk beta-glucuronidase most probably by lowering the pH of bacterial cultures in milk for optimum activity of the indigenous enzyme. The beta-glucuronidase of milk, Str. uberis and Str. agalactiae origin had similar optimum pH ranges (5.3-6.6) while E. coli beta-glucuronidase was more active at neutral or slightly alkaline pH (6.8-7.7). The increase of beta-glucuronidase activity in milk cultures of E. coli, Str. uberis, Str. agalactiae and S. aureus seemed to parallel the increase of colony forming units and were dependent on the inoculum size. The time to reach a predetermined enzyme threshold in E. coli-milk cultures showed excellent linear relationship with the inoculum size.

Animals↗