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

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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 activity of 5'-nucleotidase (EC 1.3.5), cyclic nucleotide phosphodiesterase (EC 2.1.4.17), non-specific phosphodiesterase (EC 3.1.4.1) and ribonuclease (EC 1.7.7.16)has been investigated in the seminal plasma of whole semen and in the secretions of the seminal vesicle, prostate and epididymis of the bull, boar, ram, stallion, jackass, rabbit and man. Bull seminal plasma showed the highest activity for 5'-nucleotidase, cyclic nucleotide phosphodiesterase and ribonuclease; in contrast, stallion and jackass semen were very poor in these enzymes. Ram, rabbit and boar seminal plasma showed intermediate levels for all enzymes studied. In the bull and ram, nucleolytic enzymes were found to be secreted by the seminal vesicles but in the boar, rabbit and stallion they originate mostly from the epididymis. In human seminal plasma all of the enzymes studied exhibited activity but the levels were generally lower than those recorded for the other species.
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PMID:The activity of some nucleolytic enzymes in semen and in the secretion of the male reproductive tract. 19 15

From a homogenate of rabbit colon muscle subcellular fractions were isolated by differential centrifugation. The crude microsomal fraction could be separated into subfractions, a fraction of vesicular microsomes at 35% sucrose, a fraction containing sarcolemma, mitochondrial fragments and microsomal vesicles at 35--45% sucrose and a small protein fraction at 45--55% sucrose. Their biochemical properties and their morphological characterization were investigated. The cholesterol and the phospholipid content was equally distributed between the microsomal fractions 35% and 35--45% while the RNA was localized to the mitochondria and the microsomal fraction 35%. The enzyme cytochrome c oxidase was found to be concentrated in the mitochondria while a high contamination was found in the microsomal fractions 35--45%. The NADH-oxidase activity was highest in the 35% fraction and the 5'-nucleotidase activity in the 40,000 X g supernatant. The microsomal subfractions contained the enzymes ATPase, adenylate cyclase and phosphodiesterase. In the 35% fraction Ca stimulated the hydrolysis of ATP. The binding of [3H]-ouabain and the incorporation of [3H]-leucine was most pronounced in the 35% fraction. In a K+-free Krebs Ringer medium the binding of the glucoside was stimulated in all the fractions. From these results we concluded that the fraction 35% sucrose may be mainly derived from the endoplasmic reticulum and the plasma membrane while the 35--45% originates from the plasma membrane, mitochondria and to a lesser extent the endoplasmic reticulum.
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PMID:Biochemical and morphological characterization of subcellular fractions isolated from rabbit colon muscle. 20 90

The recently discovered heat-stable inhibitor protein of the Ca2+-activated cyclic nucleotide phosphodiesterase (Sharma, R. K., Wirch, E. & Warg, J. H. (1978) J. Biol. Chem., in press) has been purified 238 214-fold from bovine brain extract using an affinity column of the modulator protein--Sepharose 4B conjugate. The purified sample appears to be homogeneous as judged by sodium dodecyl sulphate (SDS) gel electrophoresis. The protein band has a mobility corresponding to that of a polypeptide of molecular weight 68 000. Since the heat-stable inhibitor protein has a molecular weight of 70 000 under nondenaturing conditions, it suggests that it is a monomeric protein. The protein has no inhibitory activity toward the cAMP-dependent protein kinase or protein phosphatase. The purified sample has been tested for various enzyme activities which include ATPase, GTPase, cAMP phosphodiesterase, cGMP phosphodiesterase, 5'-nucleotidase, and protein kinase. None of these activities are exhibited by the purified sample.
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PMID:Purification of the heat-stable inhibitor protein of the Ca2+-activated cyclic nucleotide phosphodiesterase by affinity chromatography. 20 31

Changes in the content of cyclic nucleotides (cAMP and cGMP) and related enzyme activities were observed in the rat thyroid, pituitary and plasma during the prolonged increase of endogenous TSH produced by treatment with methylthiouracil (MTU). Experiments were performed after 4 weeks treatment with MTU. The wet weight and cAMP content per wet weight of the thyroid increased 3 and 1.4 times respectively, but cGMP showed a slight decrease. Pituitary weight increased 1.3 times, but cAMP and cGMP content did not change. The cAMP level in plasma also increased about 1.3 times, but cGMP did not increase. The cAMP-phosphodiesterase activity in the thyroid, pituitary and plasma was increased 1.9, 1.4 and 1.3 times respectively after MTU treatment, while cGMP-phosphodiesterase showed no significant change. ATPase activity in the thyroid and pituitary was also increased more than 1.5 times after MTU treatment, while 5'-nucleotidase activitity decreased remarkably. These data indicate that the metabolism of the cyclic nucleotide system in the thyroid is stimulated by TSH.
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PMID:Changes in the cyclic nucleotides of rat thyroid, pituitary and plasma caused by methylthiouracil treatment. 21 61

Fractions enriched in hCG-binding activity were prepared by differential rate centrifugation of superovulated rat ovarian homogenates and were applied to continuous sucrose density gradients (20-55%). After centrifugation at 63,000 x gav for 3.5 h, fractions of each gradient were collected and assayed for a range of marker enzyme activities characteristic of surface membranes and subcellular organelles. Mitochondria, lysosomes, and rough and smooth endoplasmic reticulum membranes accumulated in the gradient between 38-41% sucrose (1.165-1.180 g/cm3). Nuclei passed through the gradient. However, the various surface membrane markers concentrated in two distinct regions of the gradient. Alkaline phosphatase, phosphodiesterase, (Na+ + K+)ATPase I, and hCG-binding activity concentrated at 29-32% sucrose (1.120-1.135 g/cm3), whereas 5'-nucleotidase, Mg2+-dependent ATPase, and adenylate cyclase activities (and minor peaks of hCG-binding and phosphodiesterase activities) were enriched at 36-38% sucrose (1.16-1.17 g/cm3). A second ATPase, [(Na+ + K+)ATPase II], was also observed in this region of the gradient, which could be distinguished from (Na+ + K+)ATPase I of the light membrane fraction by its sensitivity to the Ca2+-chelating agent, ethylene glycol bis-(aminoethyl)tetraacetic acid (EGTA). The kinetics of binding of radioiodinated hCG to the gonadotropin receptors of the light and heavy membrane fractions were very similar. It is suggested that fractionation of superovulated rat ovaries yields two distinct populations of surface membrane material which have distinct densities and marker enzyme profiles. Furthermore, in contrast to the heavy membrane fraction, light membranes seem to possess considerable amounts of hCG receptor activity but very little adenylate cyclase.
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PMID:Interactions of gonadotropins with corpus luteum membranes. II. The identification of two distinct surface membrane fractions from superovulated rat ovaries. 21 57

Previous studies have indicated that rat luteal cells at certain stages of development can be fractionated so as to obtain two plasma membrane fractions with different densities and different profiles of marker enzymes. The light membrane fractions (density 1.13) contain the majority of hCG-binding sites and little or no cyclase enzyme, while the heavy membranes (density 1.17) contain the majority of cyclase enzyme and lesser quantities of hormone-binding sites. These membrane fractions were further compared with respect to their susceptibility to perturbation by digitonin. The buoyant density of luteal cell light membrane fractions, as marked by [125I]iodo-hCG binding, Mg2+-dependent ATPase, and 5'-nucleotidase, were highly perturbable by digotonin (delta density, greater than 0.05), while adenylate cyclase activity and phosphodiesterase activity associated with this fraction were only slightly perturbed (delta density, less than 0.02). The buoyant density of luteal cell heavy membrane fractions, as marked by adenylate cyclase, ATPase, and nucleotidase, was not significantly perturbed by digotonin. The hCG binding associated with the heavy membrane fraction was not perturbed by digitonin. From these studies, we conclude that the adenylate cyclase activity associated with light membrane fractions is due to contamination by heavy membranes, while the hCG-binding activity in heavy membrane fractions is intrinsic to that membrane. Except for the lysosomal marker (glucuronidase), which was solubilized by digitonin, the detergent had no significant effect on the density of mitochondrial, Golgi, GERL (Golgi, endoplasmic reticulum, and lysomal), or endoplasmic reticulum membranes. Plasma membranes from isolated granulosa cells and ovaries obtained 24 h after priming with PMS gonadotropin-hCG behaved as heavy membranes (density, 1.17) which contained hCG-binding sites, adenylate cyclase, nucleotidase, and Mg2+-dependent ATPase. These were not significantly perturbed by digitonin. The appearance of light membranes and the segregation of adenylate cyclase from the majority of hCG-binding sites is a development feature of the luteal cell.
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PMID:Interactions of gonadotropins with corpus luteum surface membranes. V. Differential effects of digitonin on the buoyant densities of light and heavy rat ovarian membrane fractions. 43 71

The binding of [125I]endothelin-1 (125I-ET-1) to membranes from whole rat brain, from individual brain regions, and derived from subcellular fractionation of whole rat brain was investigated. 125I-ET-1 binding to whole rat brain membranes was rapid, concentration-dependent, saturable, and characterized as irreversible because it was not displaced by unlabeled endothelin-1 (ET-1) and different concentrations of ligand produced, with time, a similar magnitude of binding. The maximum binding site capacity and second-order forward rate association constant of binding were 1,946 +/- 147 fm/mg protein and 5.53 +/- 1.72 x 10(6) M-1 s-1. Removal of either extramembranal calcium or membrane-bound calcium and calcium binding proteins did not affect the binding of 125I-ET-1 to whole rat brain membranes. The brain stem and cerebellum contained the highest levels of 125I-ET-1 binding sites, whereas the cerebral cortex, striatum, and hippocampus contained binding site levels three- to fourfold less. Subcellular fractionation of whole rat brain and subsequent analyses of the distribution of 125I-ET-1 binding demonstrated a twofold enrichment of binding sites in the synaptosomal fraction compared to the homogenate. The myelin fraction contained a similar density of binding sites compared to the homogenate, while the mitochondrial and microsomal fractions contained considerably less binding sites. The ribosomal fraction did not contain any 125I-ET-1 binding sites. The subcellular distribution of 125I-ET-1 binding sites did not correlate with the distribution of 5'-nucleotidase, cytochrome-C oxidase, phosphodiesterase, and alkaline phosphatase. Depletion of extracellular calcium increased 125I-ET-1 binding in the synaptosomal fraction but not in the myelin and mitochondrial fractions.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Regional and subcellular distribution of [125I]endothelin binding sites in rat brain. 131 99

Studies have demonstrated that augmenting the omega 6 polyunsaturated-fatty-acid (PUFA) content of N1E-115 neuroblastoma cells by media supplementation with linoleic acid results in greater than or equal to 2-fold increases in basal levels of intracellular cyclic AMP (cAMP). Data suggested some involvement of increased production of adenosine from endogenous metabolites; however, increases in adenosine were not related to increased activity of 5'-nucleotidase or decreased uptake of extracellular adenosine. PUFA-dependent elevations in basal cAMP were evident within 1 min of exposure to a phosphodiesterase inhibitor; this phenomenon did not appear to be due to PUFA-dependent changes in Ca2+ uptake or to increases in sensitivity of adenylate cyclase to Ca2+. Forskolin-stimulated cAMP formation was 3-fold higher in PUFA-enriched cells than in control cells, which suggested a direct effect on the functioning of the catalytic unit. Linoleic acid supplementation resulted in a 2-fold increase in the maximum amounts of cAMP produced in response to the stable adenosine analogue, 5'-N'ethylcarboxy-amidoadenosine (NECA). The altered stimulatory response did not involve eicosanoid formation, but may have been related to an increase in the number of stimulatory adenosine receptors, as judged by binding of [3H]NECA. These studies indicate that membrane PUFA modulate adenosine-related functions in neuroblastoma cells, and suggest that a complex series of mechanisms is involved in this regulation.
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PMID:Non-eicosanoid functions of essential fatty acids: regulation of adenosine-related functions in cultured neuroblastoma cells. 132 28

Following earlier observations that increasing the polyunsaturated fatty-acid (PUFA) content of N1E-115 neuroblastoma cells elevated basal and adenosine (Ado)-stimulated intracellular cyclic AMP (cAMP) formation, we carried out studies to determine the mechanism(s) by which PUFA exerted their modulatory effects. Basal increases in cAMP in the PUFA-enriched (PUFA+) cells were evident with short (60 sec) exposure to a phosphodiesterase inhibitor (Ro 20-1724), and increased to a maximum at 20 min; they were not observed in the absence of Ro 20-1724. Forskolin-stimulated cAMP formation in the presence of the Ro compound was 2- to 3-fold higher in the PUFA+ cells. Basal elevations in cAMP were reduced by approximately 70% by exposing the PUFA+ cells to Ado deaminase (ADA) or to an Ado antagonist, and were further increased by inhibiting ADA, which suggested that they could be producing endogenous Ado that activated stimulatory Ado receptors. However, this did not appear to involve PUFA-mediated stimulation of 5'-nucleotidase activity or inhibition of [3H]Ado uptake. Overall, the results of this study indicated that multiple mechanisms are involved in PUFA modulation of cAMP formation.
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PMID:Further studies of the mechanism(s) of polyunsaturated-fatty-acid-mediated increases in intracellular cAMP formation in N1E-115 neuroblastoma cells. 133 37

1. The enzymatic, hemorrhagic, procoagulant and anticoagulant activities of venoms of some animals including snakes, lizards, toads, scorpions, spider, wasps, bees and ants were compared. 2. Snake venom was the richest source of enzymes among the animal venoms. Most other animal venoms were devoid of phosphodiesterase, L-amino acid oxidase, alkaline phosphomonoesterase and acetylcholinesterase activities and only a few exhibited arginine ester hydrolase activity. These venoms, however, exhibited wide ranges of protease, 5'-nucleotidase and hyaluronidase activities. Most of the animal venoms examined exhibited some phospholipase A activity. 3. Other than snake venoms, only venoms of the toad Bufo calamita and the lizards were hemorrhagic, and only venoms of the social wasps, social bees and harvester ant exhibited strong anticoagulant activity. Procoagulant activity occurs only in snake venoms.
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PMID:Comparative study of the enzymatic, hemorrhagic, procoagulant and anticoagulant activities of some animal venoms. 136 Mar 87


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