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

---

Query: EC:3.2.1.31 (beta-glucuronidase)
7,680 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In a previous study of the metabolism of methyl-n-amylnitrosamine (MNAN) in the rat, 2- to 5-hydroxy-MNAN (HO-MNAN) were provisionally identified as metabolites and the identity of 4-HO-MNAN was confirmed by mass spectrometry. We now describe syntheses and mass and other spectra for 2- to 5-oxo-MNAN. Two previously unidentified MNAN metabolites were shown to be 3- and 4-oxo-MNAN. In addition to 4-HO-MNAN, we confirmed 3-HO-, 4-oxo- and (less certainly) 2-HO-MNAN as urinary MNAN metabolites by GLC-MS of HPLC fractions. Analysis with and without beta-glucuronidase treatment showed that the urinary HO-MNANs occurred as their beta-glucuronides. MNAN (25 mg/kg injected i.p.) had a blood half-life of 21 min in adult male rats. The blood also contained 4-HO- and 4-oxo-MNAN, which showed maximum levels that were 13 and 26% respectively of that for MNAN, and were cleared more slowly than MNAN. On incubation for 3 h with MNAN, rat esophagus produced 3- and 4-oxo-MNAN in yields that were 5% of those for the corresponding HO-MNANs. For MNAN metabolism, the 4-oxo-/4-HO-MNAN ratio of metabolites was 5% for adult rat liver and was 22% for adult hamster liver and 9-day-old rat liver. On incubation with 4-HO-MNAN for 3 h, oxidation to 4-oxo-MNAN was 16-25% for adult hamster or 9-day-old rat liver slices and for adult hamster liver homogenate. Homogenate activity was concentrated in the microsomal fraction, for which NAD was a more effective co-factor than NADP. A bacterial alcohol dehydrogenase oxidized 4-HO- to 4-oxo-MNAN in 38% yield/3 h. None of these preparations oxidized 2-HO- to 2-oxo-MNAN. It was concluded that 3- and 4-oxo-MNAN were metabolites of MNAN, apparently (for 4-oxo-MNAN) via HO-MNAN oxidation by a microsomal NAD-dependent enzyme, that 4-HO- and 4-oxo-MNAN formation was a major route of MNAN metabolism, and that 4-oxo-MNAN might play a role in MNAN carcinogenesis.
...
PMID:Ketonitrosamines as metabolites of methyl-n-amylnitrosamine (MNAN) and its hydroxy derivatives in the rat. 259 Oct 9

Dibutyryl cyclic adenosine 3':5'-monophosphate (DBcAMP) has been shown to inhibit glucuronidation of p-nitrophenol in a concentration-dependent manner in isolated rat hepatocytes. Adenosine (ADO) also decreased glucuronidation in a similar fashion. The effects of adenosine were examined on the variables controlling glucuronidation in intact cells. The addition of adenosine was without effect on either glucuronyltransferase or beta-glucuronidase. Adenosine decreased uridine diphosphate glucuronic acid (UDPGA) levels by 62% and, subsequently, inhibited glucuronidation by 41% in isolated rat hepatocytes. Since the synthesis of UDPGA requires NAD+ for the dehydrogenation of UDP-glucose, alterations in the redox state could account for the decrease in intracellular UDPGA levels. The effects of ADO (500 microM) on lactate and pyruvate content and redox state were examined in rat hepatocytes. ADO caused a 2.1-fold increase in lactate levels and a 2.65-fold increase in the [lactate]/[pyruvate] ratio. The NAD+/NADP ratio, therefore, was decreased by 63% in the presence of ADO. Carbohydrate reserve also affects UDPGA levels; thus, graded concentrations of glucose (5.5, 25, and 50 mM) were added to cells incubated with ADO. At 5.5 mM glucose, ADO caused a 61% decrease in glucuronide formation, while at concentrations of 25 and 50 mM glucose, the inhibition was diminished by 53 and 47% respectively. ADO appears to have decreased the synthesis of UDPGA by decreasing the NAD+/NADH ratio, thus inhibiting UDP-glucose dehydrogenase. Carbohydrate reserve also appears to be involved in the inhibition of glucuronidation mediated by ADO.
...
PMID:Effects of adenosine on glucuronidation and uridine diphosphate glucuronic acid (UDPGA) synthesis in isolated rat hepatocytes. 282 Apr 27

Dibutyryl cyclic adenosine 3':5'-monophosphate (DBcAMP) has been reported to cause numerous alterations in the activity of hepatic monooxygenase enzymes following in vivo administration or in vitro addition to intact liver preparations. In the present report the effect of the nucleotide on metabolism of p-nitroanisole (pNA) and aniline was studied in isolated rat hepatocytes. Initial studies indicated that in vitro addition of DBcAMP to hepatocytes increased metabolism of both pNA and aniline as determined by the production of oxidized metabolites, p-nitrophenol (pNP) and p-aminophenol, respectively. After enzymatic hydrolysis with beta-glucuronidase and arylsulfatase, it was determined that DBcAMP had increased accumulation of pNP formed from pNA by inhibiting further metabolism via conjugation reactions. Further studies using pNP directly as substrate confirmed the finding and revealed that glucuronidation was more sensitive to the inhibitory effect of DBcAMP than was sulfation. The 8-bromo derivative of cAMP was more potent than DBcAMP at inhibiting glucuronidation, whereas cyclic AMP and dibutyryl cyclic guanosine 3':5'-monophosphate were without effect. Noncyclic adenine nucleotides (ATP, ADP, AMP) also altered pNA and pNP metabolism. ATP and ADP increased pNP accumulation from pNA while ATP and AMP inhibited glucuronidation of pNP. DBcAMP was further found to decrease UDP-glucuronic acid levels in a concentration-dependent manner without disrupting the redox state (NAD+/NADH) in hepatocytes. The data suggest that adenine nucleotides exert a nonspecific inhibition upon glucuronidation and sulfation reactions.
...
PMID:Inhibition of glucuronidation and sulfation by dibutyryl cyclic AMP in isolated rat hepatocytes. 287 57

Within the uterine glands, the following enzymes were demonstrated by histochemical methods after 30, 58, 80, 100, and 110 d of pregnancy, respectively: beta-N-acetyl-hexosaminidase, beta-galactosidase, beta-glucuronidase, alpha-mannosidase, acid phosphatase, alkaline phosphatase, esterases, cytochrome oxidase, 5-nucleotidase, leucine aminopeptidase, adenosine triphosphatase, diaphorases (NADH, NADPH), glucose-6-phosphate dehydrogenase, 6-phosphogluconate dehydrogenase, succinate dehydrogenase, isocitrate dehydrogenase (NAD, NADP), beta-hydroxybutyrate dehydrogenase, glycero-3-phosphate dehydrogenase, NAD-glycero-3-phosphate dehydrogenase, glutamate dehydrogenase (NAD, NADP), lactate dehydrogenase. The results show that the activities of G-6-PDH, 6-PGDH, and cytochrome oxidase increase within secreting cells during the 2nd half of pregnancy. The activities of the other enzymes remained almost unchanged during the period of investigation. The description of our results distinguishes between gland neck, middle, and distal part of the secretory unit, respectively. In general, the enzyme activities are similar within the middle and distal gland segments, but lower in the epithelia of the neck region. The activity of dehydrogenases was medium to intensive within the middle and distal gland segments, but only low to medium within the neck portion. Of the hydrolases, the acid phosphatase, ATPase, leucine aminopeptidase, and beta-galactosidase demonstrated an intensive activity within activity secreting cells. The enzyme activities of the gland epithelia are compared with these of the uterine surface epithelia and the histochemical results are discussed in context with their significance in histiotrophic nutrition.
...
PMID:[Enzyme histochemistry of the pig placenta. III. Histotopics of enzymes in the uterine epithelium]. 309 49

In studies designed to reexamine the in vivo occurrence of retinyl phosphate mannose we injected hamsters intraperitoneally with either [2-3H]mannose or [15-3H]retinol and sacrificed the animals 15 min later. The small intestine was removed, the epithelial cells were scraped, and a methanolic extract of the labeled cells was prepared and chromatographed on a Mono Q anion-exchange column. Intraperitoneal administration of either [2-3H]mannose or [15-3H]retinol lead to the formation of a tritium-labeled anionic compound with a retention time on the Mono Q column similar to that of standard retinyl phosphate mannose. However, the biochemical properties of this labeled anionic compound were those expected of an organic acid and not retinyl phosphate mannose. The compound was resistant to both strong acid hydrolysis and mild base hydrolysis, as well as digestion with alpha- or beta-mannosidase, phosphodiesterase I, nucleotide pyrophosphatase, or beta-glucuronidase. When chromatographed on an Aminex HPX-87H organic acid analysis column or a silicic acid column the labeled anionic compound derived from either [2-3H]mannose or [15-3H]retinol comigrated with standard lactic acid. Treatment of the anionic compound derived from [2-3H]mannose with lactate oxidase or L-lactate 2-monooxygenase resulted in the formation of a tritium-labeled product that cochromatographed, respectively, with pyruvate or acetate on the Aminex HPX-87H column. However, treatment of the anionic compound derived from [15-3H]retinol with these same two enzymes resulted in a labeled product that migrated on the Aminex column at the same position as tritiated water. This result demonstrated that the labeled hydrogen was removed during enzymatic digestion and suggested that it was present on the second carbon of lactic acid. During the course of these studies no evidence for the in vivo labeling of a compound with the properties of retinyl phosphate mannose was found. Since [2-3H]mannose leads to labeled lactic acid in vivo the tritium label must not always be lost, as expected, during the entry step into glycolysis in which mannose 6-phosphate is converted to fructose 6-phosphate. The results suggest that an intramolecular hydrogen transfer from the C-2 position of mannose 6-phosphate to the C-1 position of fructose 6-phosphate can occur during the phosphomannose isomerase reaction. The finding that the position of the tritium label on lactic acid derived from [15-3H]retinol is on the second carbon is consistent with it coming from NADH labeled with tritium in the transferable hydrogen which was formed intracellularly during the NAD+-linked oxidation of retinol to retinaldehyde.
...
PMID:In vivo formation of tritium-labeled lactic acid from [2-3H]mannose or [15-3H]retinol by hamster intestinal epithelial cells. 357 14

In porcine areolar placental epithelia, the following enzymes were demonstrated by histochemical methods after 30, 58, 80, 100, and 110 d of pregnancy, respectively: beta-N-acetyl-hexosaminidase, beta-galactosidase, beta-glucuronidase, alpha-mannosidase, acid phosphatase, alkaline phosphatase, nonspecific esterases, cytochrome oxidase, 5-nucleotidase, leucine aminopeptidase, adenosine triphosphatase, diaphorases (NADH, NADPH), glucose-6-phosphate dehydrogenase, 6-phosphogluconate dehydrogenase, succinate dehydrogenase, isocitrate dehydrogenase (NAD, NADP), beta-hydroxybutyrate dehydrogenase, glycero-3-phosphate dehydrogenase, NAD-glycero-3-phosphate dehydrogenase, glutamate dehydrogenase (NAD, NADP), lactate dehydrogenase. The results show that the enzyme activities remained almost unchanged during the period of investigation. Of the dehydrogenases, the diaphorases as well as succinate and lactate dehydrogenase demonstrated generally an intensive activity within the epithelia. The activity of the other dehydrogenases was only low. The activity of unspecific esterase was very intensive within the uterine epithelia but remarkably low within chorionic epithelia. Contrarily, the reaction of adenosine triphosphatase was more intensive within chorionic than uterine epithelia. All investigated glucosidases reacted distinctly positive within chorionic epithelia, but only beta-N-acetyl-hexosaminidase and beta-galactosidase in uterine epithelia. The high activity of acid phosphatase, especially within the chorionic epithelium, seems to be connected with uteroferrin, an iron-binding protein. The histochemical results are discussed in context with the function of the areolae in histiotrophic nutrition and iron transport.
...
PMID:[Enzyme-histochemical studies of the pig placenta. II. Histotopics of enzymes in the areolar placenta epithelium]. 392 41

The isolation of plasma membrane from human peripheral blood monocytes is described. Monocytes were isolated by centrifugal elutriation, to eliminate an adherence step, thus minimizing functional and surface antigenic alterations to the cells. Monocytes were surface-labelled with a radiolabelled monoclonal antibody, 125I-WVH-1, and then disrupted by nitrogen cavitation. Membranes were separated according to equilibrium buoyant density by isopycnic centrifugation on a sucrose gradient. The subcellular membranes were localized using marker enzymes for the plasma membrane, 5'-nucleotidase and leucine 2-naphthylamidase (leucine aminopeptidase), and for intracellular membranes: galactosyltransferase (Golgi), arylsulfatase C (endoplasmic reticulum), monoamine oxidase (mitochondria), catalase (peroxisomes), beta-hexosaminidase and beta-glucuronidase (lysosomal vesicles) and lactate dehydrogenase (cytosol). The monoclonal antibody 125I-WVH-1 was shown to label the plasma membrane, as judged by known markers, and represents a highly specific trace label, applicable to the use of plasma membrane as an immunogen for monoclonal antibody production. The NAD-splitting enzyme, NAD+ nucleosidase, was detected and its presence on the plasma membrane was demonstrated. The subcellular localization of non-specific esterase in human mononuclear phagocytes is controversial. No evidence was found for alpha-naphthyl acetate esterase activity on the plasma membrane or in lysosomal vesicles. However, a membrane-bound esterase in fractions with properties similar to the smooth endoplasmic reticulum was detected.
...
PMID:Isolation of plasma membrane from human blood monocytes. Subcellular fractionation and marker distribution. 397 89

The accumulations by axoplasmic transport of selected enzyme activities proximal and distal to a ligature placed on the sciatic nerve were monitored in rats exposed in utero to maternal antibodies to nerve growth factor (NGF) and in control rats. Littermates of the animals exposed to anti-NGF were shown elsewhere to have had a 70% reduction in the number of sensory neurons in dorsal root ganglia and a 90% reduction in number of neurons in superior cervical (sympathetic) ganglion. The accumulation of F(-)-sensitive acid phosphatase activity was depressed 75% both proximal and distal to the tie. Accumulation of F(-)-resistant acid phosphatase activity was depressed nearly 50% proximal to the tie. Distal accumulation of this activity did not occur in either group of rats. Accumulation of acetylcholinesterase activity was depressed 30%. Distal accumulation of the activities of beta-glucuronidase and hexokinase was depressed 50%. In the lumbar dorsal root ganglia, dry weight was reduced 40%, and the activities of peroxide-sensitive, F(-)-resistant acid phosphatase and of the mitochondrial enzymes hexokinase, glutamic dehydrogenase, glutamic-oxalacetic transaminase, and NAD-dependent isocitric dehydrogenase were all reduced a little more, 45--50% per ganglion. However, the activities of the lysosomal enzymes, F(-)-sensitive acid phosphatase and beta-glucuronidase, of the peroxide-resistant, F(-)-resistant acid phosphatase, and of the mitochondrial enzyme glutaminase were all reduced about 60% per ganglion. The results of these measurements were interpreted to suggest that much, and perhaps all, of the F(-)-sensitive acid phosphatase activity in motion in peripheral nerve in rat is confined to sensory axons.
...
PMID:Transported enzymes in sciatic nerve and sensory ganglia of rats exposed to maternal antibodies against nerve growth factor. 616 7

The sub-cellular localisation of enzymes has been defined by latency analysis, and fractionation by differential centrifugation, in cell-free extracts prepared from the mycelium of Aspergillus nidulans by growth in the presence of 2-deoxyglucose followed by treatment with a mixture of beta-glucuronidase, sulphatase and beta-glucanase and exposure to N2 cavitation at 5.2 PMa. In such extracts pyruvate carboxylase and NAD-dependent and NADP-dependent glutamate dehydrogenases are exclusively localised in the cytosol whereas all the other enzymes studied have sub-cellular localisation patterns similar to those described for mammalian liver. Electrophoretic analysis has established the presence of unique mitochondrial and cytosolic isoenzymes for many of the enzymes, e.g. NAD--malate dehydrogenase, NADP--isocitrate dehydrogenase, glutamate/oxaloacetate transaminase, fumarase, which show a marked extent of incomplete latency and the presence of significant activity in the mitochondrial and cytosolic fractions prepared by differential centrifugation. A novel method is described for detection of citrate synthase activity following electrophoresis of the cell-free extract. Application of this method confirms the absence of a unique cytosolic isoenzyme of citrate synthase and hence shows that citrate synthase activity detected in the soluble fraction results from damage to the mitochondria during isolation. A scheme is proposed on the basis of these data to describe the organisation of lipid and amino acid synthesis from glucose in an organism which possesses a cytosolic pyruvate carboxylase.
...
PMID:The sub-cellular localisation of pyruvate carboxylase and of some other enzymes in Aspergillus nidulans. 634 55

In porcine interareolar placental epithelia, the following enzymes were demonstrated by histochemical methods after 30, 58, 80, 100, and 110 d of pregnancy, respectively: beta-N-acetylhexosaminidase, beta-galactosidase, beta-glucuronidase, alpha-mannosidase, acid phosphatase, alkaline phosphatase, nonspecific esterases, cytochrome oxidase, 5-nucleotidase, leucine aminopeptidase, adenosine triphosphatase, diaphorases (NADH, NADPH), glucose-6-phosphate dehydrogenase, 6-phosphogluconate dehydrogenase, succinate dehydrogenase, isocitrate dehydrogenase (NAD, NADP), beta-hydroxybutyrate dehydrogenase, glycero-3-phosphate dehydrogenase, NAD-glycero-3-phosphate dehydrogenase, glutamate dehydrogenase (NAD, NADP), lactate dehydrogenase. The results show that most of the enzyme activities remained almost unchanged during the period of investigation. Only G-6-PDH and 6-PGDH activities increased within the uterine epithelium and nonspecific esterase activity within uterine as well as chorionic epithelia during the 2nd half of pregnancy. Within chorionic and uterine epithelia, hydrolases but not dehydrogenases demonstrated a higher activity at the bases of chorionic villi as compared to the apices and flanks of the latter. The action and influence of the demonstrated enzymes on metabolism, energy transfer, secretory, and resorptive activities of chorionic and uterine epithelia are discussed.
...
PMID:[Enzyme histochemical studies of the swine placenta. Histoptics of enzymes in interareolar placental epithelia]. 643 35


<< Previous 1 2 3 Next >>

---