Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “GLUCURONIDASE”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 163 records · Page 9Linked to original sources
PubMed1986

beta-Glucuronidase in the bull seminal plasma and reproductive organs.

The biochemical distribution of beta-glucuronidase activity was studied in different reproductive organs, seminal plasma and spermatozoa of the bull. The highest specific activity was found in the epididymis, where the activity seemed to be mostly in nonsecretory and only partly in secretory form. A molecular weight of 340 X 10(3) to 360 X 10(3) was recorded for beta-glucuronidase in the bull seminal plasma and different reproductive organs with gel filtration on Sepharose 6B. In chromatofocusing four activity areas (CF-1 to CF-4) were usually obtained for beta-glucuronidase in the bull seminal plasma. The major peak CF-2 (also in the different reproductive organs) had a pI value of 5.6-5.3 and the two minor activity areas CF-1 and CF-3 had pI values of 6.0-5.8 and 5.2-4.5, respectively. Peak CF-4 eluted with a NaCl gradient after the Polybuffer elution and possibly represents an enzyme form incompletely detached from negatively charged cellular material. Isoelectric focusing on polyacrylamide gel confirmed the heterogeneity of beta-glucuronidase, since several activity bands were detected in the secretion of the different parts of the epididymis. beta-Glucuronidase activities CF-1, CF-2 and CF-3 had similar pH activity profiles (pH optimum around pH 3.0-4.0) and response to thermal inactivation at 50 degrees C. The multiple beta-glucuronidase activities of the bull seminal plasma are proposed to derive mainly from the secretion of the cauda epididymidis.

Animals↗
PubMed1977

Human beta-glucuronidase deficiency mucopolysaccharidosis: identification of cross-reactive antigen in cultured fibroblasts of deficient patients by enzyme immunoassay.

An enzyme immunoassay for human beta-glucuronidase was developed to determine the presence or absence of antigenically cross-reactive material (CRM) in patients with beta-glucuronidase deficiency mucopolysaccharidosis. This assay provided a sensitive means of measuring the primary interaction between the enzyme molecule and antibody but required neither pure antigen nor monospecific antiserum, an important consideration, since neither of these was available. Goat antiserum to partially purified human placenta beta-glucuronidase did not recognize differences in normal enzyme from human placenta, liver, fibroblasts, or blood platelets. CRM was identified in fibroblast extracts from all four of the unrelated beta-glucuronidase-deficient patients studied, but titration patterns indicated genetic heterogeneity among these four mutant proteins. Fibroblast enzymes from two obligate heterozygotes were distinguishable immunologically from normal enzyme. The enzyme immunoassay was also used to compare human enzyme with liver enzyme from other mammalian species. CRM was present in liver extracts of all species tested, but the liver enzymes, except for the rabbit, were weakly cross-reactive. We conclude that despite certain limitations, the enzyme immunoassay for human beta-glucuronidase is useful and that all four beta-glucuronidase-deficient patients studied possess CRM.

Antigens↗
PubMed2001

A novel inhibitor of beta-glucuronidase: L-aspartic acid.

Infants who consume casein hydrolysate formula have been shown to have lower neonatal jaundice levels than infants who consume routine formula or breast milk. Because casein hydrolysate has been shown to contain a beta-glucuronidase inhibitor, one possible mechanism to explain this finding is blockage of the enterohepatic circulation of bilirubin by a component of the formula. The aim of this research was to identify the source of the beta-glucuronidase inhibition in hydrolyzed casein. A beta-glucuronidase inhibition assay and measurements of physical and kinetic parameters were used to analyze the components of hydrolyzed casein and infant formulas. Kinetic studies used purified beta-glucuronidase. The L-aspartic acid in hydrolyzed casein accounts for the majority of the beta-glucuronidase inhibition present. Kinetic studies indicate a competitive inhibition mechanism. L-aspartic acid is a newly identified competitive inhibitor of beta-glucuronidase.

Aspartic Acid↗
PubMed1999

Beta-glucuronidase-inhibitory activity and hepatoprotective effect of Ganoderma lucidum.

To prove the relationship between the fluctuation in serum beta-glucuronidase level and hepatotoxicity, an inhibitor of beta-glucuronidase from G. lucidum was isolated and its hepatoprotective activity was investigated. The ether fraction of G. lucidum, which had potent beta-glucuronidase-inhibitory activity, protected against CCl4-induced liver injury. From this ether fraction, ganoderenic acid A, was isolated as the potent inhibitor of beta-glucuronidase. It had a potent hepatoprotective effect against CCl4-induced liver injury. These results suggest that the beta-glucuronidase seems to be closely related to liver injury, which could be prevented by beta-glucuronidase inhibitors.

Animals↗
PubMed1980

Comparative studies on postnatal development of liver beta-glucuronidase activity between Gunn rats and Wistar rats.

1. The changes of beta-glucuronidase activity in Wistar and Gunn strain rats from infants to adults, were determined. Consequently, the enzyme activity in liver was found to increase remarkably during the time of growth and to keep a certain level of activity at maturity. The beta-glucuronidase activity in Gunn strain rats was detected to be low in comparison with that of Wistar strain rats. 2. The beta-glucuronidase activity in liver of rats in over 50 days after birth is quite stable. It is concluded, therefore that the rats of 50-80 days old are most stable to examine the influence of drugs on beta-glucuronidase activity. 3. In the experiments using the above rats, the beta-glucuronidase activity in liver showed an increase by the administration of borneol, chloretone and barbital-Na. However, Gunn strain rats indicated rather low enzyme activity as compared to Wistar strain rats. 4. The beta-glucuronidase activity in kidney and intestine did not show an extensive alteration and was hardly affected by the drugs used.

Age Factors↗
PubMed2002

Beta-glucuronidase-mediated drug release.

The selective activation of a relatively non-toxic prodrug by an enzyme present only in the tumour should enhance the drug concentration at the tumour site and result in a better anti-tumour effect and a reduction in systemic toxicity as compared to conventional chemotherapy. beta-Glucuronidase is such an enzyme. It is normally expressed in the lysosomes of cells. In larger tumours, however, high levels of the enzyme are present in necrotic areas. Several glucuronide prodrugs have been synthesised that can be activated by beta-glucuronidase. They are relatively non-toxic due to their hydrophilic nature, which prevents them from entering cells and thus from contact with lysosomal beta-glucuronidase. The main problem of glucuronide prodrugs for clinical use is their fast renal clearance. Special attention should be paid to the development of new less hydrophilic prodrugs with slower clearance, as this would result in a prolonged exposure to beta-glucuronidase at the site of the tumour and a reduction of the amount of prodrug needed. A number of interesting anthracyclin-based glucuronide prodrugs have been synthesised and have shown favourable therapeutic effects compared to treatment with the parent drug. The tumoural levels of beta-glucuronidase can even be enhanced by two-step approaches, in which exogenous enzyme is targeted to the tumour by an antibody (ADEPT) or by the gene encoding the enzyme in transduced tumour cells (GDEPT). The ADEPT and GDEPT approaches in combination with glucuronide prodrugs have shown enhanced efficacy in experimental tumour models. Further improvement of ADEPT and GDEPT is warranted to optimise the tumour uptake and retention of antibody-enzyme fusion proteins and the efficiency and safety of current gene delivery methods. In conclusion, it is clear that glucuronide prodrugs hold promise for future use in the treatment of cancer in patients as monotherapy. Enhancement of the therapeutic effects of glucuronide prodrugs, also in patients with small tumour lesions, may possibly be achieved by techniques that target beta-glucuronidase specifically to the site of the tumour.

Animals↗
PubMed1988

Beta-glucuronidase activity related to bacterial growth in common bile duct bile in gallstone patients.

Beta-glucuronidase activity in the bile may be of importance in the etiology of pigment gallstones. This enzyme is of hepatic or bacterial origin. We have described a method to measure the activity of bacterial beta-glucuronidase in human bile, using 4-nitrophenyl-beta-D-glucopyranosiduronic acid as substrate. The method was used to measure the beta-glucuronidase activity in the bile from 51 patients with gallstone disease. This activity was related to the presence of beta-glucuronidase-producing bacteria in the bile. Escherichia coli, Bacteroides species, and Clostridium perfringens were the only species found to produce beta-glucuronidase. Patients with beta-glucuronidase-producing bacteria had on an average significantly higher enzyme activity in the bile than patients without such bacteria (p less than 0.01). The limitations of using artificial substrates in this type of studies are discussed.

Aged↗
PubMedDate not supplied

beta-Glucuronidase activity following complex coacervation and spray drying microencapsulation.

The objective was to develop a microencapsulation process suitable for the controlled release of an active protein drug. beta-glucuronidase was selected as a model protein and a combination of complex coacervation (gelatin/sodium alginate, gelatin/acacia and albumin/acacia) and spray drying was investigated. Coacervates were either spray dried or glutaraldehyde crosslinked to form microcapsules. Polyvinylpyrrolidone (PVP) and polyethylene glycol were investigated as potential coacervate enhancers and stabilizers. beta-glucuronidase/polymer mixtures were spray dried to determine any polymer protective effects on protein activity. A BUCHI 190 Spray Drier was used, beta-glucuronidase activity was determined using a Sigma Kit and microcapsule particle size was measured by Accusizer analysis (light blockage). All non-crosslinked coacervates investigated, with the exceptions of albumin/acacia and albumin/acacia/beta-glucuronidase/PVP, were unsuitable for spray drying as they rapidly phase separated and blocked the spray drier nozzle. beta-glucuronidase activity in the albumin/acacia coacervates approximated to 99% prior to and 80% following spray drying. This can be compared to activities of approximately 30% and 68% when spray dried alone and with albumin, respectively, and of 18% in albumin/acacia microcapsules crosslinked with glutaraldehyde. Microcapsule particle size was affected by coacervation pH, additives and spray drying. In vitro beta-glucuronidase release was biphasic, with an initial burst release followed by a zero order release phase and continued over the 12 day study period. In conclusion, the spray drying albumin/acacia/PVP method described is useful for the preparation and collection of controlled release microcapsules with minimal loss of beta-glucuronidase activity.

Acacia↗
PubMed2000

Bacterial amylolytic activity enhances beta-glucuronidase expression of amylase-negative Escherichia coli strain in starch-medium.

The possibility of associating starch degradation with bacterial beta-glucuronidase expression was examined. We proved that starving, in starch medium, amylase-negative Escherichia coli (M94) which has constitutive beta-glucuronidase greatly reduces (p < 0.01) its background activity, but the addition of both cell-free supernatants or cells of Bacillus subtilis (B10) producing amylase greatly increases (p < 0.01) the E. coli beta-glucuronidase activity. Increases in activity were maximal when amylase in the medium ranged from 0.3 to 0.8 U ml-1 and pH from 6.8 to 6.3, whereas higher amylase activity interacted with E. coli viability and the effect on beta-glucuronidase was less evident. The impact of B. subtilis amylase on E. coli beta-glucuronidase induction, observed when the organisms were co-cultured, indirectly supports the hypothesis that amylolytic activity of hindgut bacteria may be effective on beta-glucuronidase induction of the climax microflora. This last finding is important in the health field, considering the implication between the deconjugating role of this enzyme and consequent activation of toxic and carcinogenic compounds.

Amylases↗
PubMed2003

Beta-glucuronidase in the diagnosis of bacterial meningitis and response to treatment.

AIM: Beta-glucuronidase activity is increased in the cerebrospinal fluid (CSF) of patients with bacterial meningitis. The aim of this study was to investigate the beta-glucuronidase activity in the cell-free CSF of bacterial meningitis and its course during treatment, and compare it with other CSF parameters. METHODS: The beta-glucuronidase activity, cell number, protein concentration and CSF/blood glucose ratio were measured in 43 consecutive infants and children with bacterial meningitis, and 97 control subjects. Patients had one or two follow-up lumbar punctures. RESULTS: The beta-glucuronidase activity was increased early in bacterial meningitis, even when the other CSF parameters were undisturbed. Before treatment, the median activity in affected children was 136 micromoles 4-methylumbelliferone l(-1) h(-1) (range 44-826) and in controls 14 (7-23). In all patients who improved, the activity was lower in the follow-up CSF samples. Six to 12 h after starting treatment, the median activity was already reduced by 59%. The other CSF parameters showed a variability during the first 24 h of treatment independently of the course of the disease. Multiple comparisons of the CSF parameters in 17 patients who had two follow-up punctures showed that the beta-glucuronidase activity was the best prognostic index. CONCLUSION: Beta-glucuronidase activity in the CSF is a reliable indicator of bacterial meningitis, which can identify the response to treatment early in the course of illness. The enzyme activity is increased early in the disease, even when the other laboratory parameters from the CSF remain normal.

Adolescent↗
PubMed1991

[Serum level of beta-glucuronidase as potential indicator of disease activity in rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE)].

The lysosomal enzyme beta-glucuronidase is involved in the degradation of glycosaminoglycans to monosaccharides. beta-glucuronidase-activity has been found to correlate well with histomorphological changes in active arthritis. By use of a new--enzyme kinetic--assay serum activity of beta-glucuronidase was measured in 32 patients with rheumatoid arthritis (RA) and 23 patients with systemic lupus erythematodes (sLE) and compared to 120 healthy volunteers. In 72% of the patients with RA and 65% of the patients with sLE increased beta-glucuronidase-activity was found (greater than 97.5. percentile of healthy volunteers). There was no correlation with an estimated score of disease activity, duration of morning stiffness, or blood sedimentation rate. The determination of beta-glucuronidase revealed increased serum levels in most of the patients with RA and sLE. The role of beta-glucuronidase as a predictor of joint destruction remains to be evaluated in a prospective study. For this evaluation the use of the enzyme-kinetic method described here is recommendable.

Adult↗
PubMed1979

Comparison of serum and urine fibrin split products and urinary beta-glucuronidase in the diagnosis of renal transplant rejection.

This study compares the usefulness of serum and urine fibrin split products and the urinary enzyme, beta-glucuronidase, in the diagnosis and management of renal transplant rejection. Fibrin split products, determined by a tanned human red cell agglutination inhibition immunoassay, were measured as a reflection of the secondary fibrinolysis from fibrin deposited in the renal microvasculature as a result of rejection. Urinary beta-glucuronidase, expressed as the ratio of enzyme activity to creatinine concentration, was determined by a colorimetric technique following dialysis of urine to remove endogenous activators and inhibitors. Activity of this lysosomal enzyme is thought to reflect tubular injury. Twenty-nine renal transplant recipients (15 from living donors and 14 from cadaver donors) were evaluated. Both serum and urinary fibrin split products and urinary beta-glucuronidase were markedly elevated in the immediate postoperative period, probably reflecting ischemic trauma. Acute rejection occurring within the first three months was associated with elevations of fibrin split products (particularly urine) and beta-glucuronidase. Elevated values returned to normal following successful treatment with steroids and/or heparin, but remained high in the presence of continued rejection. After the first 48 hours post-transplant, in the absence of rejection, values for fibrin split products were within the normal range. Urinary beta-glucuronidase remained elevated if the transplanted kidney was recovering from acute tubular necrosis. Fibrin split products and urinary beta-glucuronidase were usually normal in chronic rejection.

Clinical Laboratory Techniques↗
PubMed1979

Demonstration of a rat liver microsomal binding protein specific for beta-glucuronidase.

A binding protein with apparent specificity for beta-glucuronidase has been partially purified from a Triton X-100 extract of rat liver microsomes by affinity chromatography on glucuronidase-Sepharose 2B. It appears that once removed from the membrane, this binding protein self-aggregates to form large macromolecular complexes. With the use of polyacrylamide gel electrophoretic and sucrose density gradient ultracentrifugation assays to monitor the conversion of glucuronidase tetramer to a very high molecular weight complex, it was shown that the binding activity is heatlabile and protease-sensitive. However, binding activity is not influenced by salts, carbohydrates, other proteins or glycoproteins, or by extensive periodate oxidation of beta-glucuronidase, nor does binding occur with any other protein tested. The binding protein does not discriminate against any form of beta-glucuronidase from any rat organ tested. However, the binding protein does show organ localization, being present in the liver and kidney but not the spleen. The possible relationship of this binding protein to egasyn, a membrane protein which stabilizes beta-glucuronidase in mouse liver endoplasmic reticulum, is discussed.

Animals↗
PubMedDate not supplied

pH-dependent rearrangement of the biosynthetic ester glucuronide of valproic acid to beta-glucuronidase-resistant forms.

A major metabolite of the antiepileptic drug valproic acid (VPA) in animals and man is the glucuronic acid conjugate, which is cleaved by incubation with beta-glucuronidase (specific for 1-O-substituted-beta-D-glucopyranosiduronic acids) or hydrolysis in strong acid or alkali. Previous studies revealed that an often substantial proportion of the alkali-labile conjugated VPA in stored urine or bile samples was not hydrolyzed by beta-glucuronidase, suggesting the presence of nonglucuronide conjugates. In the present study, bile from a NaVPA-treated rat was preincubated at 37 degrees C for 3 hr at pH values from -0.8 to 12.9, and then analyzed for nonconjugated VPA, VPA released by hydrolysis with beta-glucuronidase, and VPA released by hydrolysis with alkali. At pH 3-7, all alkali-labile conjugated VPA remained susceptible to beta-glucuronidase hydrolysis, whereas at pH 0-3 and 7-11, a proportion became resistant to the enzyme. GLC and GC/MS analysis of trimethylsilyl derivatives of the intact conjugates revealed the appearance of seven additional peaks, adjacent to the biosynthetic ester glucuronide, of which six were structural isomers and one was a dehydrated species. The data were consistent with acid- and base-catalyzed intramolecular acyl migration of the valproate moiety away from the C-1 position, with subsequent processes of ring-opening, mutarotation, and lactonization yielding structural isomers and lactones which were not substrates for beta-glucuronidase. It was further shown that these rearrangements are time- and temperature-dependent. Consequently, sample handling and storage conditions of ester glucuronides prior to analysis are of prime importance, since hydrolysis with beta-glucuronidase is frequently used for identification and quantification of glucuronides.

Animals↗
PubMed1978

Turnover of kidney beta-glucuronidase in normal and Chédiak-Higashi (beige) mice.

Kidney beta-glucuronidase turnover has been examined by specific antibody methods in normal C57BL/6J mice and in coisogenic C57BL/6J beige mice, an animal model for the human Chédiak-Higashi syndrome. No effect of the beige gene on the rate of glucuronidase synthesis was detected in either untreated or testosterone-treated mice. Moreover, glucuronidase of beige mice decayed relatively slowly in pulse labeling and in hormone withdrawal experiments. Direct measurements of secretion confirmed that both in the presence of testosterone and following its withdrawal, there was a threefold lower rate of secretion of kidney glucuronidase in beige mice. Following hormone withdrawal, the loss of glucuronidase activity in beige mice was biphasic, with the second more slowly turning over component apparently lost by a nonsecretory mechanism. This persistent nonsecreted glucuronidase activity was specifically associated with giant lysosomes in kidney proximal tubule cells near the corticomedullary border. Thus, there are two major populations of lysosomes in proximal tubule cells of beige mice. Cells of the outer cortex contain mainly morphologically normal lysosomes, and their lysosomal enzymes are secreted at near normal rates. However, lysosomal enzymes derived from the giant lysosomes of cells near the corticomedullary border are secreted either very slowly or not at all. The altered secretion of lysosomal enzymes from specific kidney cells of beige mice may serve as a model system for study of defective fusion of lysosomes with phagocytosed bacteria in cells of Chédiak-Higashi patients.

Animals↗
PubMed1980

Studies on the alpha-L-iduronidase activity of beta-glucuronidase preparations from bovine liver, rat liver, and rat preputial gland.

A commercial preparation of bovine liver beta-glucuronidase contained two distinct enzyme species, both of which catalyze the hydrolysis of 4-methylumbelliferyl alpha-L-iduronide. The species with a molecular weight of about 290,000 was devoid of phenyl alpha-L-iduronidase activity and exhibited 4-methylumbelliferyl beta-D-glucuronidase activity. The species with a molecular weight of about 78,000 was active towards phenyl alpha-L-iduronide but lacked the latter activity. Studies of the kinetics of inhibition and heat inactivation suggested that the hydrolysis of 4-methylumbelliferyl alpha-L-iduronide is due to the beta-glucuronidase in the case of the 290,000-dalton species. The highly purified beta-glucuronidase preparations derived from rat preputial gland and liver lysosomes also exhibited 4-methylumbelliferyl alpha-L-iduronidase activity. These findings support the view that beta-glucuronidase can hydrolyze certain alpha-L-iduronide bonds and raise the possibility that beta-glucuronidase may play a role in the catabolism of iduronic acid-containing glycosaminoglycans.

Animals↗
PubMed1980

Quantitation of cis versus trans regulation of mouse beta-glucuronidase. Action of alleles of the Gus-r locus determining androgen inducibility.

Genetic studies have shown that the induction of beta-glucuronidase in mouse kidney in response to androgens is under the control of the Gus-r gene, closely linked to the beta-glucuronidase structural gene, Gus-s, on mouse Chromosome 5. Despite the fact that a single structural gene codes for beta-glucuronidase, enzyme molecules show considerable charge heterogeneity, presumably as a result of post-translational events. Because the enzyme is a tetramer, this heterogeneity has complicated examination of the cis versus trans action of the Gus-r gene. In order to resolve the problem, we have developed a quantitative method for determining the amount of beta-glucuronidase derived from each structural allele in mice heterozygous for beta-glucuronidase electrophoretic mobility. The method involves separation and quantitation of genetically variant cyanogen bromide peptides from the enzyme. Using this technique, we show that Gus-r acts cis, suggesting that it directly affects the template activity of the glucuronidase structural gene.

Alleles↗
PubMed1993

C-terminal processing of human beta-glucuronidase. The propeptide is required for full expression of catalytic activity, intracellular retention, and proper phosphorylation.

beta-Glucuronidase undergoes proteolytic C-terminal processing during or after its transport to lysosomes or endosomes. We determined the C-terminal processing site for human placental beta-glucuronidase to be the peptide bond between Thr633-Arg634. To evaluate the role of the 18-amino acid peptide removed in C-terminal processing, we changed the codon for Arg634 to a stop codon by site-directed mutagenesis and studied expression of the truncated mutant enzyme in COS-7 cells. An increased fraction of newly synthesized enzyme from R634Stop cDNA was secreted. Pulse-chase experiments provided no evidence for increased degradation of the intracellular R634Stop enzyme. The total amount of catalytic activity expressed from the R634Stop mutant cDNA was only half that seen with the wild type cDNA, and the Kcat of the mutant enzyme was 52% that of wild type enzyme. These results indicate that the C-terminal propeptide in the precursor is important for beta-glucuronidase to achieve maximal activity. The truncated enzyme formed hybrid tetramers in cotransfection experiments with the cDNA for rat beta-glucuronidase. There appeared to be no decrease in stability of the R634Stop enzyme, since chaotropic agents, heat treatment, and pH had similar effects on the mutant and the wild type enzymes. The uptake rate of the truncated mutant (R634Stop) enzyme by beta-glucuronidase-deficient human fibroblast cells was only 55-60% that of the wild type enzyme. Binding to the immobilized cation-independent mannose-6-phosphate receptor and measurement of the 32P-labeled phosphorylated oligosaccharides revealed that the truncated mutant enzyme was 32-34% less phosphorylated and appeared to contain proportionately more covered phosphate groups than the wild type enzyme. These results suggest that the propeptide influences the accessibility to both processing enzymes that produce the mannose-6-phosphate recognition marker on beta-glucuronidase.

Amino Acid Sequence↗