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

Experiments over the past decade have revealed a third component in the autonomic nervous system which is neither adrenergic nor cholinergic. These nerves are strongly represented in the gastrointestinal tract of a wide range of vertebrate species and have also been identified in lung, trachea, retractor penis, bladder, oesophagus, eye, seminal vesicle and in some parts of the cardiovascular system and brain. Evidence has been presented that the principal active substance released by these nerves in the gut is a purine nucleotide, probably ATP, and they have therefore been termed 'purinergic'. The evidence includes: (1) synthesis and storage of ATP in nerves; (2) release of ATP from the nerves when they are stimulated; (3) mimicry by exogenously applied ATP of the action of nerve-released transmitter; (4) the presence of Mg2+-activated ATPase, 5'-nucleotidase and adenosine deaminase, enzymes which inactivate ATP; (5) the similar blocking and potentiating effects produced by drugs on the responses to exogenously applied ATP and nerve stimulation. A tentative model for the synthesis, storage, release and inactivation of ATP during purinergic nerve transmission is proposed. Some properties of purinergic receptors are described.
 ...
PMID:The purinergic nerve hypothesis. 2 31

A study has been made on the structure and chemical composition of the gut of Haemonchus contortus (Rud., 1803). The oesophagus has typically a triradiate, cuticle-lined lumen. The intestinal epithelium is provided with a well-developed brush border which contains periodic acid-Schiff-positive mucoproteins. The intestinal epithelium stores glycogen and lipids. It stains diffusely for phospholipids and general proteins and also for terminal-NH2 group. The presence of Fe2+ and Fe3+ containing pigments and activities of acid and alkaline phosphatases, glucose-6-phosphatase, and 5'-nucleotidase have been observed in the intestinal epithelium. Biochemically pH optimum for intestinal acid phosphatase has been found to be 4.8. The brush border shows positive reactions for acid phosphatase and glucose-6-phosphatase, and negative reactions for alkaline phosphatase and 5'-nucleotidase, and negative reactions for alkaline phosphatase and 5'-nucleotidase. The presence of enzymes in the brush border is related to extracellular digestion and absorption of nutrients.
 ...
PMID:Morphological, histochemical, and biochemical studies on the gut of Haemonchus contortus Rud., 1803). 21 48

5'-Nucleotidase prepared from muscle of small intesting of pig is strongly inhibited by nucleoside di- and triphosphates and their phosphonate analogs. Substrate kinetics appromate the Michaelis-Menten for for AMP, which shows a Km of 3-6 muM at pH 5.3-7.2. Inhibition is characterized as partial competitive, except at pH 5.3, where inhibition by ATP is noncompetitive. The Ki values for several inhibitors have been determined, and their departure from completeness of competitive inhibition has been studied. Inhibitor cooperativity of the type reported for the enzyme from sheep brain (P. L. Ipata (1968), Biochemistry 7, 507) was not observed for the enzyme from gut. In addition we failed to confirm sigmoid inhibition kinetics with 5'-nucleotidase from sheep brain.
 ...
PMID:5'-Nucleotidase from smooth muscle of small intestine and from brain. Inhibition of nucleotides. 116 62

Receptor binding of the opioid receptor antagonist, [3H]diprenorphine, which has a similar affinity to the various opioid receptor subtypes, was characterized in subcellular fractions derived from either longitudinal or circular smooth muscle of the canine small intestine with their plexuses (myenteric plexus and deep muscular plexus, respectively) attached. The distribution of opioid binding activity showed a good correlation in the different fractions with the binding of the neuronal marker [3H]saxitoxin but no correlation to the smooth muscle plasma membrane marker 5'-nucleotidase. The saturation data (Kd = 0.12 +/- 0.04 nM and maximum binding = 400 +/- 20 fmol/mg) and the data from kinetic experiments (Kd = 0.08 nmol) in the myenteric plexus were in good agreement with results obtained previously from the circular muscle/deep muscular plexus preparation. Competition experiments using selective drugs for mu [morphiceptin-analog (N-MePhe3-D-Pro4)-morphiceptin] ), delta (D-Pen2,5-enkephalin) and kappa (dynorphin 1-13, U50488-H) ligands showed the existence of all three receptor subtypes. The existence of kappa receptors was confirmed in saturation experiments using [3H] ethylketocycloazocine as labeled ligand. Two putative opioid agonists, with effects on gastrointestinal motility, trimebutine and JO-1196 (fedotozin), were also examined. Trimebutine (Ki = 0.18 microM), Des-Met-trimebutine (Ki = 0.72 microM) and Jo-1196 (Ki = 0.19 microM) displaced specific opiate binding. The relative affinity for the opioid receptor subtypes was mu = 0.44, delta = 0.30 and kappa = 0.26 for trimebutine and mu = 0.25, delta = 0.22 and kappa = 0.52 for Jo-1196. Thus, Jo-1196 had some selectivity for kappa receptors compared to trimebutine. We conclude that there are similar types of opioid receptors in the myenteric plexus and the deep muscular plexus and that specificity of function of opioid nerves must depend on differential location of receptor types on particular neurons. The action of trimebutine and related drugs could vary depending upon their interactions with various gut opioid receptors having different physiological roles.
 ...
PMID:Interaction of trimebutine and Jo-1196 (fedotozine) with opioid receptors in the canine ileum. 185 39

Membrane vesicles, showing a 21 +/- 2-fold enrichment in the activity of 5'-nucleotidase and a 11 +/- 4-fold enrichment in the activity of angiotensin-converting enzyme relative to homogenate, were prepared from the myenteric plexus-containing longitudinal muscle layer of guinea pig ileum. Incubation of the vesicles with substance P and neurokinin A led to degradation of the peptides, and metabolites were isolated by reverse-phase HPLC and identified by amino acid composition. Cleavages of substance P between Glu6-Phe7, Phe7-Phe8, and Gly9-Leu10 and of neurokinin A between Gly8-Leu9 were observed and could be inhibited in a dose-dependent manner by phosphoramidon, an inhibitor of neutral endopeptidase 24.11. Formation of these metabolites was not completely inhibited by this agent, indicating that a phosphoramidon-insensitive form of endopeptidase 24.11 was present in the gut. Substance P was resistant to degradation by aminopeptidases, but neurokinin A was a substrate for bestatin-sensitive aminopeptidase(s), so that the neurokinin A (3-10) fragment represented the predominant metabolite in the chromatograms. The rate of formation of all the metabolites was not inhibited by enalapril and not enhanced by an increased Cl- concentration, indicating that angiotensin-converting enzyme was unimportant in the degradation process. Degradation of neurokinin A by the vesicles (Km 30 microM; Vmax 7.2 +/- 0.8 nmol min-1 mg of protein-1) was more rapid than degradation of substance P (Km 25 microM; Vmax 4.4 +/- 0.4 nmol min-1 mg of protein-1).
 ...
PMID:Proteolytic inactivation of substance P and neurokinin A in the longitudinal muscle layer of guinea pig small intestine. 242 10

The influence of lysophosphatidylcholine (LPC) on macromolecular permeability in the distal ileum has been studied. Using a rat experimental model, we determined the intestinal permeability to different sized dextrans (3000-70 000 daltons) and bovine serum albumin (BSA) in the absence and presence of LPC. We also examined the morphology of the ileal mucosa after deposition of LPC in the gut lumen, and determined N-acetyl-beta-glucosaminidase, 5'-nucleotidase, and alkaline phosphatase activities in suspensions of isolated mucosal cells and different concentrations of LPC. We found that 20 mM LPC damaged the ileal mucosa and that it increased its permeability to all the molecules investigated. Moreover, mixtures of mucosal cells and 0.01-1 mM LPC showed increased N-acetyl-beta-glucosaminidase activity: the higher the LPC concentration, the higher the enzyme activity. These findings indicate that LPC, a naturally occurring surfactant in the intestine, might damage mucosal cells and release lysosomal enzyme activity, and that higher LPC concentrations may impair the mucosal barrier function and increase the gut permeability to macromolecules such as proteins. This could have relevance to the development of various disease states, in which increased intestinal absorption of macromolecules is of importance.
 ...
PMID:Lysophosphatidylcholine increases rat ileal permeability to macromolecules. 257 78

The influence of two surface-active food additives on the integrity and permeability of rat ileal mucosa has been studied. We determined the activity of N-acetyl-beta-glucosaminidase, a lysosomal enzyme, in the rat intestinal lumen after deposition of polyoxyethylene (20) sorbitan monostearate (polysorbate 60; Tween 60) or polyoxyethylene (20) sorbitan monooleate (polysorbate 80; Tween 80) in a section of ligated, cannulated gut. We also determined the activities of N-acetyl-beta-glucosaminidase, alkaline phosphatase, 5'-nucleotidase and phospholipase A2 in mixtures of isolated mucosal cells and polysorbate 60 or polysorbate 80. The activity of N-acetyl-beta-glucosaminidase was increased in the luminal contents of the cannulated gut 15 min after deposition of either polysorbate 60 or polysorbate 80 (10 mg/ml fluid instilled into gut). It was also increased in mixtures of mucosal cells and polysorbate 60 or polysorbate 80 (0.1-10 mg/ml). In contrast, the activities of alkaline phosphatase and 5'-nucleotidase were unaffected and that of phospholipase A2 was decreased by the presence of either polysorbate. These findings indicated that polysorbate 60 and polysorbate 80 released lysosomal enzymes from the intestinal mucosal cells and that these agents might damage the intestinal mucosa and increase its permeability. We therefore determined the intestinal permeability to sodium fluorescein in the absence and presence of polysorbate 60 or 80 and found that the permeability was slightly increased in the presence of either of the compounds at concentrations of 10 mg/ml fluid instilled into gut. It is possible therefore that surface-active food additives might impair the function of the mucosal barrier and increase the permeability of the gut to potentially toxic and pathogenic molecules.
 ...
PMID:Influence of surface-active food additives on the integrity and permeability of rat intestinal mucosa. 609 20

The effect of a bacterial extract orally administered to 20 children with recurrent infections of the upper respiratory tract, was investigated in a double-blind study. The composition of the peripheral blood mononuclear cells (T and B-lymphocytes, monocytes) and some of their biochemical properties (5'-nucleotidase, beta-N-acetyl-glucosaminidase and non-specific esterase) were unaffected. In contrast, the allogeneic mixed lymphocyte reaction was significantly increased in patients treated with the bacterial extract. In the treated group the number of infectious episodes decreased significantly and the clinical response correlated positively with the mixed lymphocyte reaction. These findings suggest that the bacterial extract has the capacity of restoring depressed immune functions by acting through the gut-associated lymphoid tissue.
 ...
PMID:Clinical and immunobiological effects of an orally administered bacterial extract. 623 40

The effect of a bacterial extract orally administered to 20 children with recurrent infections of the upper respiratory tract was investigated in a double-blind study. The composition of the peripheral blood mononuclear cells (T and B lymphocytes, monocytes) and some of their biochemical properties (5'-nucleotidase, beta-N-acetyl-glucosaminidase and non-specific esterase) were unaffected. In contrast, the allogeneic mixed lymphocyte reaction was significantly increased in patients treated with the bacterial extract. In the treated group the number of infectious episodes decreased significantly and the clinical response correlated positively with the mixed lymphocyte reaction. These findings suggest that the bacterial extract has the capacity to restore depressed immune functions by acting through the gut-associated lymphoid tissue.
 ...
PMID:[Clinical and immunobiological action of an orally administered bacterial extract]. 623 82

Incubation of adult Schistosoma mansoni at 37 degrees C in chemically defined media caused the shedding of variable amounts of the parasite's tegument. In phosphate-buffered saline, pH 7.4, 37% of 125I-labelled wheat germ agglutinin which was attached to the schistosome surface was released within 5 min. When the released material was collected by centrifugation at 55 000 g for 1 h, the pellet was seen to consist of components of the parasite tegument and contained 1% of the parasite protein and 6.2% of the 5'-AMPase activity. By monitoring the release of the gut enzyme, haemoglobinase, it was shown that predominantly tegumental material was released under these conditions. The material released from the parasite was separated by discontinuous sucrose gradient centrifugation into 4 major fractions and it was shown that a material banding at low density was highly enriched in vesicles of parasite outer membrane. Major polypeptides of apparent molecular weights 135 000, 110 000, 90 000, 65 000, 47 000 and 40 000 and glycoproteins of apparent molecular weights 135 000, 120 000, 65 000, 63 000 and 30-40 000 were identified in this fraction. Comparison of the distribution of 5'-AMPase activity and the contents of each fraction as revealed by ultrastructural examination showed that this enzyme is a good marker for the tegumental outer membrane.
 ...
PMID:Isolation and partial characterization of the tegumental outer membrane of adult Schistosoma mansoni. 626 45


1 2 Next >>