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:3.6.1.3 (ATPase)
65,361 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Cellular membranes were prepared from the non-extending part of dark grown hypocotyls of Phaseolus aureus. The relative effectiveness of continuous and discontinuous sucrose gradient centrifugation for the separation of membranes was investigated. Characteristic densities of membranes were determined by the localization of enzyme activities on continuous sucrose gradients: NADH-cytochrome c-reductase for endoplasmic reticulum, beta-1-3-glucan synthetase for plasma-membrane and IDPase for dictyosomes. The difficulties involved in the application of ATPase and IDPase as specific membrane markers are discussed. Negative staining of isolated fractions indicated that intact dictyosomes could be prepared from this tissue without the use of chemical fixatives in the homogenization medium. Extraction of isolated membranes showed that carbohydrate-binding proteins (lectins) were present both in an easily removable and in a more strongly bound form. In vivo incorporation of D-[U-14C]glucose and subsequent isolation and solubilization of the different membranes showed that sugar-containing polymers could be released without hydrolytic techniques and were present in the equivalent extracts that exhibited lectin activity. The possibility of lectin-polysaccharide complexes in endoplasmic reticulum and dictyosomes and their involvement in the synthesis and transport of secretory substances by the membranes is discussed.
...
PMID:Characterization, enzymatic and lectin properties of isolated membranes from Phaseolus aureus. 18 22

A method for isolating a plasma membrane-enriched fraction and other subcellular fractions from rat mesenteric arteries by the use of a discontinuous sucrose density gradient is decribed. Electron microscopy showed both plasma membrane and endoplasmic reticulum fractions to be composed of vesicles. 5'-Nucleotidase, alkaline phosphatase, ouabain-sensitive (Na+ + K+)-ATPase and K+-phosphatase, and phosphodiesterase I were concentrated in the plasma membrane fraction. The increase in ATP-dependent calcium uptake in the presence of oxalate was greater in the endoplasmic reticulum than in the plasma membrane fraction. The lack of inhibition of active calcium uptake by azide suggests that the plasma membrane-enriched fraction was relatively free of mitochondrial contamination. Calcium uptake by the plasma membrane or the endoplasmic reticulum fraction was not enhanced by high-energy compounds other than ATP, and was little affected by 100 mM KCl or NaCl in the Mg++-containing medium. Subcellular fractions isolated by this method will be useful for investigating the biochemistry of small blood vessels of the rat.
...
PMID:Isolation and characterization of plasma membrane from rat mesenteric arteries. 18 63

In this first paper of a series comparing the membranes of normal lymphocyte populations from male outbred Syrian hamsters with those of neoplastic transformants (GD 248) induced by simian virus 40, a method is described for the isolation of representative plasma membrane (PM) fragments from both cell types. Multiple criteria were used to monitor the purity and yield of PM material after cell disruption by nitrogen cavitation and after membrane fractionation by a combination of differential centrifugation and isopyknic ultracentrifugation in dextran density gradients. Lactoperoxidase-catalyzed radioiodination before cell disruption was used as an extrinsic surface marker; Na+,K+-activated ATPase, as well as alkaline phosphatase, was used as intrinsic functional PM markers. The distribution of nuclei, mitochondria, lysosomes, and endoplasmic reticulum (ER) during fractionation was monitored by the measurement of DNA, succinate dehydrogenase and monoamine oxidase, beta-glucuronidase and glucose-6-phosphatase, and NADH:lipoamide oxidoreductase, respectively. According to the three PM markers employed, a 15- to 20-fold purification (over homogenate) and a PM yield of about 65% were obtained for both cell categories, with negligible contamination by DNA, mitochondria, lysosomes, and er. The procedure also allowed recovery of 60% of the mitochondria free of other cell elements.
...
PMID:Membranes of normal hamster lymphocytes and lymphoid cells neoplastically transformed by simian virus 40. I. High-yield purification of plasma membrane fragments. 18 92

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.
...
PMID:Biochemical and morphological characterization of subcellular fractions isolated from rabbit colon muscle. 20 90

A histochemical technique for the demonstration of K+-rho-nitrophenylphosphatase (K+-rhoNPPase) activity, a component of the Na+,K+-ATPase, has been applied at the fine structural level in the somatosensory cortex of the rat. Reaction product was consistenly found in dendrites and in association with the cytoplasmic aspect of the dendritic plasmalemma. Reaction product often filled portions of the tubular smooth endoplasmic reticulum in these processes. The results of these studies are interpreted to indicate that enzymatic activity is associated with large-and small-diameter dendrites. No convincing evidence of high activity was found in glial profiles. The importance of neurons and their dendrites in active transport of sodium and potassium ions in the cerebral cortex may be more significant than indicated by studies with isolated neurons and glia.
...
PMID:Fine structural localization of potassium-stimulated rho nitrophenylphosphatase activity in denrites of the cerebral cortex. 20 62

Ultrastructural distribution of acid phosphatase and adenosine triphosphatase was studied in the receptor elements of HERBST and GRANDRY sensory corpuscles. Acid phosphatase activity was established in the elements of smooth and rough endoplasmic reticulum of perineural capsule cells, as well as in the secondary lysosomes of all cell types. Particular interest was paid on the activity of myelin-like dense bodies and some clear core vesicles belonging to the axoplasm of receptor nerve fibres. Adenosine triphosphatase activity was established on the membranes of receptor structures and pinocytotic vesicles. More deposits of electron dense material were localized on the axolemma of the non-myelinated portions of the receptor nerve fibres. The functional significance and importance of the both enzymes in the receptor structures was discussed.
...
PMID:Cytochemical localization of acid phosphatase and adenosine triphosphatase in some avian mechanoreceptors. 21 19

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.
...
PMID:Interactions of gonadotropins with corpus luteum membranes. II. The identification of two distinct surface membrane fractions from superovulated rat ovaries. 21 57

Luminal (brush border) and antiluminal (basal-lateral) membranes were isolated from canine renal cortex. The enzyme marker for luminal membrane, alkaline phosphatase was enhanced 19-fold and the antiluminal enzyme marker, (Na+ + K+)-ATPase, was enhanced 22-fold in their respective membrane preparation, while the amount of cross contamination was minimal. Contamination of these preparations by enzyme markers for lysosomes, endoplasmic reticulum and mitochondria was also low. Routinely, more than 50 mg membrane protein was isolated for each membrane. Electron micrographs showed that the membranes were uniform in size, appearance, and vesicular in nature. An examination of the orientation of these membranes showed that 76.5% of the antiluminal membranes and 86% of the luminal membranes were right-side out.
...
PMID:Isolation of luminal and antiluminal membranes from dog kidney cortex. 22 Oct 18

An aqueous two phase polymer system (Dextran-polyethyleneglycol system was developed for isolation of plasma membrane fraction from nerves of the crayfish, Procamburus clarkii. The polymer system effectively reduced both mitochondrial and endoplasmic reticulum marker enzyme activity from a crude membrane fraction. The similar enrichment of (Na+ + K+)-ATPase (ATP phosphohydrolase, EC 3.6.1.3) was shown by the polymer system as well as by the sucrose density gradient centrifugation. The purified plasma membrane fraction (PM) was obtained using the polymer system followed by sucrose density gradient centrifugation. The PM fraction had a high specific activity of (Na + K+)-ATPase of up to 17 times that in the homogenate, with smaller contamination by mitochondria and endoplasmic reticulum enzyme activities than any other membrane fraction. Electron micrographs of the PM fraction also supported the above evidences. The protein recovered from the PM fraction amounted to 1.1% of the total protein in the homogenate. The specific activity of acetylcholinesterase (acetylcholine hydrolase, EC 3.1.1.7) in the membrane fractions was less increased than that of (Na+ + K+)-ATPase. Sodium dodecyl sulphate-polyacrylamide gel electrophoresis suggested that polypeptide chains of estimated molecular weight 115,000 and 31,000 were enriched in the plasma membranes of the crayfish nerves.
...
PMID:Isolation of neuronal plasma membranes from the crayfish Procamburus clarkii, with an aqueous two phase polymer system followed by sucrose density gradient centrifugation. 22 29

Dual localization of acid phosphatase in lysosomal and extralysosomal sites of the tubule epithelial cells of normal mouse kidney was observed at the light and electron microscope level using a modified Gomori lead-salt method with p-nitrophenylphosphate (pNPP) as substrate. Based on previous biochemical and cytochemical findings, we developed optimal conditions for the enzyme activity in extralysosomal sites. The conditions used for the light microscopic level consisted of 1.5 mM PNPP, 2.0 MM Pb(NO3)2 and 0.05 M acetate buffer (pH 5.8). Those for the electron microscopic study required 3.0 mM PNPP, 3.6 MM Pb(NO3)2 and 0.1 M acetate buffer (pH 5.8). This modified lead-salt technique was highly specific and provided a suitable method for the demonstration of nonlysosomal as well as lysosomal sites of acid phosphatase activity in the tubule epithelial cells of normal mouse kidney. As expected, the enzyme activity appeared in the lysosomes, but the prominent reaction in the brush border, the rough endoplasmic reticulum and basal infolding plasma membranes was not anticipated. We were able to demonstrate in situ organelle precursors of microsomal acid phosphatase such as endoplasmic reticulum, plasma membrane and basal infolding membranes showing the same substrate preference, which had been observed previously in biochemical studies in our laboratory. Since the possible participation of alkaline phosphatases, K+-pNPPase or Na+-K+-adenosine triphosphatase was ruled out by use of appropriate inhibitors, the enzyme-reactive sites can be interpreted as reflecting nonspecific acid phosphatase.
...
PMID:Demonstration of lysosomal and extralysosomal sites for acid phosphatase in mouse kidney tubule cells with p-nitrophenylphosphate lead-salt technique. 23 53


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>

---