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 distribution of [3H]oxytocin binding sites among various subcellular fractions of rat myometrium paralleled the distribution of 5'-nucleotidase, a plasma membrane marker enzyme, but not of NADPH-cytochrome c reductase or succinate-cytochrome c reductase, which are endoplasmic reticulum and mitochondrial marker enzymes respectively. [3H]Oxytocin binding to the most enriched plasma membrane fraction showed the degree of selectivity with respect to hormone analogues that is expected for the oxytocin receptor. The binding of oxytocin to this fraction showed an apparent Kd of 1.98 X 10(-9) M and a capacity of 1.28 pmol mg-1. It is concluded that the oxytocin receptor is located on the plasma membrane of the smooth muscle cells of the rat uterus.
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PMID:Localization of the oxytocin receptor in the plasma membrane of rat myometrium. 20 28

In the livers from young (3-6 month) and old (30 month) C57/BL mice and BN/Bi rats light microscope histochemistry has shown that enzyme activity is not always distributed evenly throughout the lobule. The mitochondrial enzyme succinic dehydrogenase, the plasma membrane enzyme 5'-nucleotidase and the endoplasmic reticulum enzyme glucose-6-phosphatase showed heavier reaction product in the perioportal regions of the lobule compared with the centrilobular regions. Alkaline phosphatase showed an altered distribution pattern with age: in young livers this was uniform throughout the lobule while in old livers there was enhanced peripoertal activity. Electron microscope cytochemistry showed that this was due to increased numbers of bile canaliculi in this region containing reaction product and to the additional presence of reaction product associated with the microvilli lining the space of Disse.
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PMID:Differential enzyme distribution in lobules of livers from young and old mice and rats. 20 21

1. The subcellular distribution and maturation of Ruthenium Red-insensitive Ca(2+) transport activity were determined in livers of rats ranging in age from 3 days pre-term to 10 weeks of adult life and compared with those of glucose 6-phosphatase, 5'-nucleotidase and Ruthenium Red-sensitive Ca(2+) transport. Initial rates of Ruthenium Red-insensitive Ca(2+) transport were highest in those fractions enriched in glucose 6-phosphatase, i.e. the microsomal fraction; this fraction was devoid of Ruthenium Red-sensitive Ca(2+) transport activity. Although the heaviest fraction (nuclear) contained significant amounts of 5'-nucleotidase activity it was devoid of Ruthenium Red-insensitive Ca(2+) transport activity. 2. Foetal rat liver contain minimal amounts of Ruthenium Red-insensitive Ca(2+) transport activity, glucose 6-phosphatase and 5'-nucleotidase activities. These begin to be expressed concomitantly soon after birth; Ruthenium Red-insensitive Ca(2+) transport is maximal by 3 to 4 days and remains so for up to at least 10 weeks of adult life. Glucose 6-phosphatase also reaches a peak at 3-4 days, but then rapidly decreases to approach adult values. Maximal activity of 5'-nucleotidase in the microsomal and nuclear fractions is seen about 4-6 days after birth; this enzyme activity remains increased for up to about 10 days and then falls, but not as rapidly as glucose 6-phosphatase. It is tentatively suggested that the bulk of the Ruthenium Red-insensitive Ca(2+) transport is attributable to the system derived from the endoplasmic reticulum. 3. Administration of glucagon to adult rats enhances by 2-3-fold the initial rate of Ruthenium Red-insensitive Ca(2+) transport in the intermediate but not the microsomal fraction. The hormone-induced effect is fully suppressed by co-administration of puromycin, is dose-dependent with half-maximal response at approx. 1mug of glucagon/100g body wt. and time-dependent exhibiting a half-maximal response about 1h after administration of the hormone. 4. Ruthenium Red-insensitive Ca(2+) transport in the post-mitochondrial fraction of foetal liver also responds to the administration in situ of glucagon. The response, which also is prevented by co-administration of puromycin, is maximal in those foetuses nearing term. The suggestion is made that these effects of the hormone on Ruthenium Red-insensitive Ca(2+) transport are an integral part of the physiological network in the liver cell.
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PMID:The subcellular location, maturation and response to increased plasma glucagon of ruthenium red-insensitive calcium-ion transport in rat liver. 21 18

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

Highly purified nuclei isolated from bovine corpora lutea showed marked enrichment of NAD pyrophosphorylase, a marker for this organelle. Rough endoplasmic reticulum and lysosomal markers were undetectable, whereas plasma membrane and Golgi markers were detectable but not enriched in nuclei. These highly puridied nuclei exhibited specific binding with 125I-labeled human choriogonadotropin, [3H]prostaglandin E1 and [3H]prostaglandin F2 alpha. However, these bindings were only 15.4% (human choriogonadotropin), 7.9% (prostaglandin E1) and 8.9% (prostaglandin F2 alpha) of the plasma membrane binding observed under the same conditions. Washing of nuclei and plasma membranes twice with buffer containing 0.1% Triton X-100 resulted in gonadotropin and prostaglandin F2 alpha binding site and 5'-nucleotidase (EC 3.1.3.5) losses from nuclei that were different from those observed for plasma membranes. More importantly, the washed nuclei exhibited 44% (human choriogonadotropin), 21--26% (prostaglandins) of original specific binding despite virtual disappearance of 5'-nucleotidase activity. The nuclear membranes isolated from nuclei, specifically bound 125I-labeled human choriogonadotropin and [3H]prostaglandin F2 alpha to the same extent or significantly more ([3H]prostaglandin E1, P less than 0.05) than nuclei themselves, despite the marked losses of chromatin. In summary, our data suggest that gonadotropin and prostaglandins bind to nuclei and that this binding was intrinsic and was primarily associated with the nuclear membrane.
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PMID:Gonadotropin and prostaglandins binding sites in nuclei of bovine corpora lutea. 22 42

The iodothyronine-deiodinating enzymes (iodothyronine-5- and 5'-deiodinase) of rat liver were found to be located in the parenchymal cells. Differential centrifugation of rat liver homogenate revealed that the deiodinases resided mainly in the microsomal fraction. The subcellular distribution pattern of these enzymes correlated best with glucose-6-phosphatase, a marker enzyme of the endoplasmic reticulum. Plasma membranes, prepared by discontinuous sucrose gradient centrifugation, were found to contain very little deiodinating activity. Analysis of fractions obtained during the course of plasma membrane isolation showed that the deiodinases correlated positively with glucose-6-phosphatase (r larger than or equal to 0.98) and negatively with the plasma membrane marker 5'-nucleotidase (r ranging between -0.88 and -0.97). It is concluded that the iodothyronine-deiodinating enzymes of rat liver are associated with the endoplasmic reticulum.
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PMID:Location of rat liver iodothyronine deiodinating enzymes in the endoplasmic reticulum. 22 68

3T3 and SV3T3 mouse embryo cells and a variety of other monolayer cell lines can be induced to form and shed plasma membrane vesicles by exposure to sulphydryl blocking agents including formaldehyde and N-ethyl malemide. Morphological studies show that multiple vesicles are formed and released from individual cells and that the vesicle membrane is continuous with the plasma membrane of the cell. Vesicles measure from o.1 to 15 micrometer in diameter and are free of detectable contamination with cytoplasmic membranes and organelles. Vesicles also show a 10-fold enrichment in the plasma membrane marker enzyme 5'-nucleotidase and are devoid of detectable NADH-cytochrome C reductase and succinic dehydrogenase activity which are marker enzymes for endoplasmic reticulum and mitochondria, respectively. Vesicles have a high cholesterol: phospholipid ratio and show enrichment in sphingomyelin content. They contain receptors for Con A and WGA, approximately 20 size class polypeptides and intramembranous particles. These results suggest that vesicles are derived from and have the general characteristics of plasma membranes.
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PMID:Plasma membrane vesiculation in 3T3 and SV3T3 cells. I. Morphological and biochemical characterization. 37 Jan 29

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 overall transport of bile salts across the hepatocyte is characterized as a carrier-mediated process whose rate-limiting step is biliary secretion. Specific bile salt binding proteins have been identified in liver surface membrane fractions and were postulated to represent the initial interaction in bile salt translocation across both the sinusoidal and canalicular membranes. To test this hypothesis, cycloheximide was administered to rats to inhibit hepatic protein synthesis. 16 h after cycloheximide administration [14C]leucine incorporation into hepatic protein was inhibited by 93% at 1 h and 47% at 12 h. However, values of liver function tests were not increased, although serum albumin, serum alanine amino-transferase, and alkaline phosphatase were significantly decreased. Light and electron microscopy did not demonstrate necrosis or fat accumulation. The latter demonstrated minimal disorganization of rough endoplasmic reticulum and occasional lamellar whorls. 16 h after cycloheximide administration bile salt independent bile flow, basal bile salt excretion, and basal bile flow were unaltered, but the maximum bile salt transport capacity was reduced to 62% of control and 24 h later to 38%. Decreased bile salt transport was reversible, for it returned to control values after 48 h, when hepatic protein synthesis was also normal. Maximum bromosulfophthalein (BSP) transport, on the other hand, was reduced after 16 h to only 85% of control. Both bile salt and BPS maximum transport capacities decreased with time during inhibition of protein synthesis, apparently following first order kinetics. It was estimated that their half-lives are 20 h for bile salt transport and 55 h for BSP transport. These different turnover rates suggest that cycloheximide does not decrease active transport through generalized hepatic dysfunction or alteration of high energy sources possibly required for transport. The maximum number of [14C]cholic acid binding sites in liver surface membrane fractions was determined by an ultrafiltration assay. They were reduced to 68% of control after 16 h of cycloheximide and to 25% after 24 h. This reduction in the number of binding sites is apparently selective, for the activities of the liver surface membrane enzymes (Na+-K+)ATPase, Mg++-ATPase, and 5'-nucleotidase were not significantly changed. The associated alterations in bile salt transport and the maximum number of binding sites after cycloheximide administration suggests that these receptors may be the bile salt carriers.
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PMID:Regulation of hepatic transport of bile salt. Effect of protein synthesis inhibition on excretion of bile salts and their binding to liver surface membrane fractions. 43 30

Mitochondrial and microsomal fractions were isolated from guinea pig myocardium by differential pelleting. The mitochondrial fraction was subjected to analytical subfractionation by sucrose density gradient centrifugation and the gradient fractions assayed for marker enzymes for the various mitochondrial compartments, viz outer membrane (monoamine oxidase), intermembranous space (adenylate kinase), inner membrane (Mg2+-dependent ATPase and cytochrome c oxidase) and mitochondrial matrix (malate dehydrogenase), and for creatine kinase. Both creatine kinase and adenylate kinase were released by suspending the mitochondria in 50 mmol . litre-1 sodium phosphate buffer. Sonication or disruption with the detergent, digitonin released the adenylate kinase but the creatine kinase remained associated with the inner membranes. Subsequent salt treatment desorbed the creatine kinase from these membranes. It is concluded that creatine kinase is located to the outer aspect of the inner mitochondrial membrane. Analytical subfractionation of the microsomal fraction clearly resolved markers for the sarcolemma (5'-nucleotidase), outer mitochondrial membrane (monoamine oxidase) and endoplasmic reticulum (neutral alpha-glucosidase and RNA). Creatine kinase was localised in the endoplasmic reticulum particularly the smooth membranes.
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PMID:Sub-mitochondrial and sub-microsomal distribution of creatine kinase in guinea pig myocardium. 51 58


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