Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.3.5 (5'-nucleotidase)
 3,167 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The oral mucosa of developing and mature rats was analyzed histochemically for regional enzyme differences. The following enzymes were studied: nonspecific alkaline phosphatase (alkpase), acid phosphatase (acidpase), 5'-nucleotidase (AMPase), adenosine triphosphatase (ATPase), succinate dehydrogenase (SDH), lactate dehydrogenase (LDH), and glucose-6-phosphate dehydrogenase (G-6-pDH). All enzymes were active in the oral mucosa, but regional as well as tissue variations were observed. Epithelium in all regions showed acidpase staining. Oxidoreductases were found in all regions with variations within the epithelium. The epithelium of specific regions stained for alkpase and AMPase, while adjacent epithelium did not. We suggest that the alkpase and AMPase activities are associated with specific functions of the epithelium in these regions.
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PMID:Enzyme histochemistry of developing rat oral mucosa. 720 47

Prolactin proteolysis by rat pituitary homogenates was assayed by measuring the release of trichloroacetic acid-soluble peptides from 125I-labelled rat prolactin. There was a distinct optimum at pH 4.3, with only trace amounts of activity at neutral and alkaline pH. Rat pituitary homogenates were subjected to analytical subcellular fractionation by sucrose density gradient centrifugation in a Beaufay automatic zonal rotor. The principal organelles were characterized by their respective marker enzymes, including: cytosol (lactate dehydrogenase); plasma membrane (5'-nucleotidase); lysosomes (N-acetyl-beta-glucosaminidase, beta-glucuronidase); mitochondria (particulate malate dehydrogenase); endoplasmic reticulum (neutral alpha-glucosidase); prolactin granules (radioimmunoassayable prolactin). Acid prolactin protease had a similar distribution to the lysosomal marker enzymes. A localisation of the activity to lysosomes was confirmed by subcellular fractionation experiments in which the lysosomes were selectively disrupted with low concentrations of the membrane perturbant, digitonin. Experiments with specific inhibitors of the lysosomal cathepsins indicate that both cathepsins B and D are implicated in pituitary prolactin proteolysis.
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PMID:Analytical subcellular fractionation of rat pituitary homogenates, with special reference to prolactin proteolysis by lysosomes. 729 6

Analytical subcellular fractionation techniques using metrizamide density gradients have been used to investigate the properties of the gut hormone storage granules and the principal organelles from homogenates of normal human jejunal mucosa obtained by peroral mucosal biopsy. The individual hormones, detected by radioimmunoassay, each showed single discrete peaks in the density gradient experiments indicating localisation to single granules each with characteristic modal densities. Thus motilin showed a modal density of 1.15, gastrin 1.16, gastric inhibitory polypeptide (GIP) 1.17, enteroglucagon 1.18 and somatostatin and vasoactive intestinal peptide (VIP) 1.10 g/ml. The following organelles, characterised by their marker enzymes were located in the density gradients; plasma membrane (5'-nucleotidase) brush border (alpha-glucosidase, pH 6.0) mitochondria (particulate malate dehydrogenase), peroxisomes (catalase), lysosomes (N-acetyl-beta-glucosaminidase), endoplasmic reticulum (alpha-glucosidase, pH 8.0), cytosol (lactate dehydrogenase). These studies provide biochemical evidence of the distinct nature of the individual gut hormone storage granules and provide a basis for studying dynamic changes in the granules in response to physiological stimuli and pathological processes.
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PMID:Characterisation of gut hormone storage granules from normal human jejunum using metrizamide density gradients. 730 92

The protein concentration in bile from several species is reported. The changes in output of protein, bile salts and several enzymes have been followed in rat bile over a 48 h cannulation period. Bile-salt concentration dropped rapidly owing to interruption of the enterohepatic circulation but the output of protein, lysosomal enzymes [acid phosphatase (EC 3.1.3.2) and beta-D-glucuronidase (EC 3.2.1.31)] and plasma-membrane enzymes [5'-nucleotidase (EC 3.1.3.5) and phosphodiesterase I (EC 3.1.4.1)] was maintained. Liver cell damage, monitored by output of lactate dehydrogenase, was very low throughout. Protein, lysosomal enzymes and plasma-membrane enzymes showed different patterns of output with time, but all showed a net increase between 12 and 24 h. The output of lysosomal and plasma-membrane enzymes was between 1 and 5% of the total liver complement over the first 24 h; if inhibition by biliary components is taken into account the output of some of these enzymes, particularly acid phosphatase, may be greater. Ultracentrifugation of bile showed that as the concentration of bile salts decreases the proportion of plasma-membrane enzymes in a sedimentable form increases. The results are discussed in relation to other studies of biliary proteins and to studies of the perturbation of membranes and cells with bile salts.
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PMID:Enzymes and proteins in bile. Variations in output in rat cannula bile during and after depletion of the bile-salt pool. 730 64

(1) Chemiluminenscence of rat polymorphonuclear leukocytes was stimulated by a phagocytic stimulus, latex beads (diameter = 1.01 micrometer). The maximum chemiluminescent intensity increased with bead concentration in the range 0.2--20 x 10(9) beads/ml. This response was abolished in the absence of extracellular Ca2+ (1 mM EGTA). (2) Chemiluminescence could also be stimulated by the Ca2+ ionophore A23187 in the presence of extra-cellular calcium. (3) Addition of human serum, as a source of complement, to rat polymorphonuclear leukocytes preincubated with anti-5'-nucleotidase serum resulted in a rapid stimulation of chemiluminescence, after a lag of about 40 s. (4) The stimulation of chemiluminescence by antibody plus complement was not the result of cell lysis because (i) no significant release of lactate dehydrogenase was detected at the time of the chemiluminescent response (ii) chemiluminescence was associated with the cells and not the surrounding media (iii) cell lysis did not produce chemiluminescence. (5) Chemiluminescence stimulated by antibody plus complement or by beads was inhibited by the 'calmodulin-blocker', trifluoperazine (50% inhibiton with approximately 20--30 microM). (6) Cu2+ (10(-4) M), which can inhibit C9 action, inhibited the rapid rise in chemiluminescence induced by antibody plus complement, but not the bead-induced chemiluminescence. (7) Depletion of C9 from human serum markedly inhibited the complement induced chemiluminescence response. Addition of purified C9 restored the response. (8) It was concluded that formation of the terminal complement attack complex at the surface of rat polymorphonuclear leucocytes induces a Ca2+-dependent chemiluminescence in the cells, in the absence of cell lysis.
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PMID:Stimulation of Ca2+-dependent chemiluminescence in rat polymorphonuclear leucocytes by polystyrene beads and the non-lytic action of complement. 731 54

The conjugated trihydroxy bile salts glycocholate and taurocholate removed approx. 20--30% of the plasma-membrane enzymes 5'-nucleotidase, alkaline phosphatase and alkaline phosphodiesterase I from isolated hepatocytes before the onset of lysis, as judged by release of the cytosolic enzyme lactate dehydrogenase. The conjugated dihydroxy bile salt glycodeoxycholate similarly removed 10--20% of the 5'-nucleotidase and alkaline phosphatase activities, but not alkaline phosphodiesterase activity; this bile salt caused lysis of hepatocytes at approx. 10-fold lower concentrations (1.5--2.0mM) than either glycocholate or taurocholate (12--16mM). At low concentrations (7 mM), glycocholate released these enzymes in a predominantly particulate form, whereas at higher concentrations (15 mM) glycocholate further released these components in a predominantly 'soluble' form. Inclusion of 1% (w/v) bovine serum albumin in the incubations had a small protective effect on the release of enzymes from hepatocytes by glycodeoxycholate, but not by glycocholate. These observations are discussed in relation to the possible role of bile salts in the origin of some biliary proteins.
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PMID:Effects of bile salts on the plasma membranes of isolated rat hepatocytes. 739 66

The effect of carrot extract on carbon tetrachloride (CCl4)-induced acute liver damage was evaluated. The increased serum enzyme levels (viz., glutamate oxaloacetate transaminase, glutamate pyruvate transaminase, lactate dehydrogenase, alkaline phosphatase, sorbitol and glutamate dehydrogenase) by CCl4-induction were significantly lowered due to pretreatment with the extract. The extract also decreased the elevated serum bilirubin and urea content due to CCl4 administration. Increased activities of hepatic 5'-nucleotidase, acid phosphatase, acid ribonuclease and decreased levels of succinic dehydrogenase, glucose-6-phosphatase and cytochrome P-450 produced by CCl4 were reversed by the extract in a dose-responsive way. Results of this study revealed that carrot could afford a significant protective action in the alleviation of CCl4-induced hepatocellular injury.
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PMID:Hepatoprotective activity of carrot (Daucus carota L.) against carbon tetrachloride intoxication in mouse liver. 750 Jun 38

Rabbit cornea (control or infected with herpes virus) was studied at different time periods after the infection. The change of both ultrastructure and topochemistry of lactate dehydrogenase, adenosine triphosphatase, 5'-nucleotidase is found. The alteration of phosphohydrolase ultracytochemistry is probably due to the enzyme mechanisms which are responsible for reproduction of the herpes simplex virus. Further study of herpetic keratitis enzymology will allow better understanding of the pathogenesis and improve the treatment of herpetic keratitis.
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PMID:[Ultrastructural and ultracytochemical analysis of herpes infected cornea]. 798 38

A total of 25 apparently healthy adults (13 men and 12 women), 29.5 years (SD = 3.6 years) of age, served as subjects in a 24-h study conducted in Barcelona, Spain, in the spring of 1990. The group had a homogeneous pattern of meals, activity, and behavior. Six blood samples were collected at 4-h intervals over a single 24-h period beginning at 10:00 h. The oral temperature was measured at 2-h intervals to facilitate an independent biological time reference for the local population being studied. The serum concentration of 12 enzymes of clinical interest were measured in each sample: creatine kinase, creatine kinase 2, alanine aminotransferase, aspartate aminotransferase, gamma-glutamyltransferase, alkaline phosphatase, cholinesterase, lactate dehydrogenase, lactate dehydrogenase 1, 5'-nucleotidase, pancreatic alpha-amylase, and triacylglycerol lipase. We supposed that all experimental data obtained for a quantity came from a single "hypothetical subject" that represented the central tendency of the population and then these data were analyzed for circadian rhythm by single cosinor. A statistically significant circadian rhythm was detected in all quantities studied (p < or = 0.05) except for serum concentrations of pancreatic alpha-amylase and triacylglycerol lipase. The maximum daily rhythmic variation was approximately 10% (interval, 6-14%) for all quantities studied except pancreatic alpha-amylase (2.6%). This rhythmic variation is greater than the analytical variation except for 5'-nucleotidase and pancreatic alpha-amylase. The acrophases for the quantities studied (except that of triacylglycerol lipase) coincide with times near those of the oral temperature acrophase (18:01 local time). The results of this study will doubtless contribute to further documentation of the structure of the human circadian timing system and to establishment of time-qualified reference intervals for a defined group of subjects.
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PMID:Circadian rhythms of serum concentrations of 12 enzymes of clinical interest. 810 Apr 88

The absorption enhancement and presystemic degradation kinetics of a homologous series of acyclovir 2'-ester prodrugs were investigated in rats using the in situ nasal perfusion technique in the presence of bile salt-fatty acid mixed micelles. In vitro incubation studies indicated that nasal perfusate containing a mixed micellar solution generated higher ester-cleaving activity than isotonic phosphate buffer washings. Inhibitor screening and substrate specificity studies demonstrated the enzyme to be most likely carboxylesterase rather than true cholinesterase. The extent of prodrug cleavage by the carboxylesterase appears to correlate well with the substrate lipophilicity for esters with linear acyl chains. On the other hand, branching of the acyl side chain significantly retards acyclovir prodrug breakdown. To estimate the nasal epithelial membrane and cytoplasmic damaging effect caused by sodium glycocholate (NaGC)-linoleic acid (15 mM:5 mM) mixed micelles, the release profiles of 5'-nucleotidase (5'-ND), lactate dehydrogenase (LDH), and carboxylesterase in the nasal perfusate were measured as a function of time. The results indicated that the activities of all three enzymes resulting from the mixed micellar solution appeared to be significantly higher than those caused by 15 mM NaGC alone. The apparent nasal absorption rate constants of acyclovir and its butyrate, valerate, pivalate, and hexanoate ester prodrugs in mixed micellar solutions containing an esterase inhibitor (1 mM phenylmethylsulfonyl fluoride) were individually calculated. Without an inhibitor, lengthening of the linear acyl side chain of the prodrug resulted in greatly accelerated degradation coupled with moderate absorption improvement. The solubilities and micellar binding constants of acyclovir prodrugs were also determined.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Bile salt-fatty acid mixed micelles as nasal absorption promoters. III. Effects on nasal transport and enzymatic degradation of acyclovir prodrugs. 816 83


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