Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:O95477 (membrane-bound)
 29,236 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The purification of detergent-solubilized membrane-bound phosphatases from Zymomonas mobilis using novel adsorbents is described. The prepared adsorbents have a hydrophobic core with functional groups attached. These functional groups may either increase or decrease the hydrophobicity of the adsorbent, or participate in other forms of interactions. Adsorption of acid phosphatase (ACP), alkaline phosphatase (ALP) and ATPase to these adsorbents was salt-promoted. Desorption was achieved by decreasing the salt concentration or by displacement with increasing concentration of Triton X-100. The results indicate that chromatography on multifunctional adsorbents that are predominantly hydrophobic in character is a procedure that can have a general applicability in purification of membrane proteins.
 ...
PMID:The use of multifunctional adsorbents to purify membrane-bound phosphatases from Zymomonas mobilis. Purification of acid phosphatase, alkaline phosphatase and ATPase. 136 73

Spermidine dehydrogenase found in the membrane fraction of Citrobacter freundii IFO 12681 was solubilized with Triton X-100 and further purified to homogeneity. The properties of the membrane enzyme were almost identical to those obtained from the soluble fraction of the organism with respect to molecular and catalytic properties. Thus, binding properties of the enzyme to the bacterial membrane were checked. The ratio of enzyme activity found in the soluble fraction to the membrane fraction was dependent on salt concentration during cell disruption. A hydrophobic interaction was largely involved in anchoring the enzyme to the membrane fraction. Purified spermidine dehydrogenase from the soluble fraction was readily adsorbed into the membrane fraction in the presence of salt. Spermidine dehydrogenase appeared to be a membrane-bound enzyme localized in the cytoplasmic membranes in a manner that makes a partial release of the enzyme possible during mechanical cell disruption. When spermidine oxidation was done with the resting cells of C. freundii, a stoichiometric formation of two reaction products, 1,3-diaminopropane and gamma-aminobutyraldeyde, was observed without any lag time. These facts indicate that the enzyme is localized on the outer surface of the cytoplasmic membranes or in the periplasmic space of the organism.
 ...
PMID:Characterization of membrane-bound spermidine dehydrogenase of Citrobacter freundii. 136 91

The effects of four bile salts, one fusidate derivative, and one mixed micellar formulation of bile salt-fatty acid combination on the nasal mucosal protein and enzyme release have been investigated in rats using an in situ nasal perfusion technique. Deoxycholate (NaDC) was found to possess the maximum protein solubilizing activity, followed by taurodihydrofusidate (STDHF), cholate, glycocholate (NaGC), and taurocholate (NaTC) in a descending order. The difference in protein solubilization of NaDC and NaGC was further characterized by the release of 5'-nucleotidase (5'-ND), a membrane-bound enzyme, and lactate dehydrogenase (LDH), an intracellular enzyme, in the perfusate. While both NaDC and NaGC caused comparable 5'-ND release from nasal membrane, intracellular LDH release was significantly higher with NaDC. The greater protein and LDH solubilizing effects of NaDC corresponded well with its faster rate of disappearance from the nasal perfusate. Therefore, the dihydroxy bile salt NaDC tends to cause intracellular damage and cell lysis, whereas the trihydroxy bile salt NaGC appears to produce primarily mucosal membrane perturbations. Linoleic acid in the form of soluble mixed micelles with glycocholate caused a further increase in nasal protein release. However, the rate and extent of nasal membrane protein release by the mixed micelles composed of 15 mM glycocholate and 5 mM linoleic acid were significantly lower than those caused by either deoxyholate or STDHF at the same concentrations. Nasal absorption of acyclovir, a non-absorbable hydrophilic model antiviral agent, was found to be enhanced in the presence of conjugated trihydroxy bile salts and bile salt-fatty acid mixed micelles.(ABSTRACT TRUNCATED AT 250 WORDS)
 ...
PMID:Nasal membrane and intracellular protein and enzyme release by bile salts and bile salt-fatty acid mixed micelles: correlation with facilitated drug transport. 140 2

After i.v. injection of 125I-labeled rat atrial natriuretic factor ([125I] ANF; 99-126) in tracer dose to mice, a saturable binding to lung membranes was evidenced using a filtration assay. Analysis of the membrane-bound radioactivity by high-pressure liquid chromatography indicated that it corresponded to the intact hormone in sinorphan-treated mice. [125I]rANF binding was inhibited completely by i.v. administration of rANF with an ED50 of 1.0 +/- 0.1 nmol/kg, a value obtained in sinorphan-treated mice. SC 416,542, an ANF analog with a four amino acid deletion in its ring, representing a selective ligand of ANF clearance receptors, was as potent as rANF in inhibiting the in vivo binding. By contrast, ANF fragments produced by enkephalinase (EC 3.4-24.11, membrane metalloendopeptidase) were less potent or even inactive in competing with [125I]rANF. It is concluded that [125I]rANF binding to lung membranes in vivo occurs to clearance receptors. [125I]rANF binding was enhanced by more than 2-fold in mice receiving enkephalinase inhibitors such as sinorphan and, although to a lesser extent, aminopeptidase inhibitors; on the other hand inhibitors of a variety of other peptidases were ineffective. These data confirm by a novel approach that enkephalinase plays a key role in the inactivation of circulating ANF. Hence, the in vivo binding test can be used to assess the activity of clearance receptor ligands and peptidase inhibitors, two classes of drugs affecting ANF metabolism, with potential clinical utility in cardiovascular and salt-retaining diseases.
 ...
PMID:Binding of [125I]atrial natriuretic factor to mouse lung membranes in vivo: characterization and effects of peptidase inhibitors. 153 34

Activation of human neutrophils involves the degranulation of specific and azurophil granules. This process is GTP-dependent and the presence of small GTP-binding proteins (SGBPs) has been detected in the two granule populations. At present, none of these SGBPs has been definitely identified. In order to characterize some of these proteins and obtain further insights as to their potential role in degranulation processes, we have used specific antibodies directed against the ras-related rap1 and rap2 proteins. By immunoblot analysis, we observed that rap2p is predominantly located in specific granules, whereas rap1p is detected both in specific granules and a fraction enriched in plasma membranes. Neither rap1p nor rap2p was found in the cytosol or in azurophil granules. Similarly, by indirect immunofluorescence, we observed that cytoplasmic granules were stained with anti-rap1p antibodies and anti-rap2p antibodies, and the plasma membrane was labeled with both antibodies but more distinctly with anti-rap1p than with anti-rap2p antibodies. rap1p and rap2p are tightly bound to the membrane of specific granules since they cannot be extracted by high salt or alkaline buffers. In addition, treatment of intact specific granules with pronase induced the degradation of rap proteins suggesting that they are exposed to the cytoplasmic face of the granules. Degranulation of neutrophils consists of the translocation and subsequent fusion of granules with the plasma membrane. Activation of this process induced the accumulation of rap proteins in the plasma membrane as observed by subcellular fractionation and indirect immunofluorescence experiments; this was not associated with the appearance of a soluble form of these proteins, showing that they remain membrane-bound during this process. The identification and subcellular localization of rap1p and rap2p at the surface of specific granules and the observation that they translocate to the plasma membrane upon cell stimulation without appearance of soluble forms constitute an important step toward the understanding of their physiological functions in human neutrophils.
 ...
PMID:Association of rap1 and rap2 proteins with the specific granules of human neutrophils. Translocation to the plasma membrane during cell activation. 155 42

Ferritin is a typical intracellular protein but small amounts are also present in serum and other biological fluids. The source and physiological significance of serum ferritin are still obscure. The presence of ferritin mRNAs on polysomes bound to endoplasmic reticulum (ER) could be relevant for the secretion of ferritin. By Northern blot analysis we found significant amounts of both L and H subunit mRNAs on rat liver membrane-bound polysomes. Immunoprecipitation of translational products of membrane-bound polysomes with anti-rat liver ferritin antibody showed that ferritin is actually synthesized on ER membranes. Analysis of RNA extracted from salt-washed rat liver microsomes demonstrated that ferritin mRNAs are translated by polysomes tightly bound to ER membranes. Following iron treatment, both the amount of H and L subunit mRNAs and ferritin synthesis increased sharply in both free and bound polysomal fractions. Translation of membrane-bound polysomes in the presence of microsomal membranes indicated that ferritin is not processed by signal sequence cleavage or glycosylation and is not translocated into ER membranes. Ferritin mRNAs found on membrane-bound polysomes are associated with ER in a specific way, however, their products do not seem to follow the classic secretory pathway and therefore the significance of the large amount of ferritin mRNAs in the bound ribosome fraction remains unclear.
 ...
PMID:Ferritin mRNAs on rat liver membrane-bound polysomes synthesize ferritin that does not translocate across membranes. 161 Aug 92

Extracellular membrane-bound vesicles (called matrix vesicles) which occur in abundance in atherosclerotic blood vessels are believed to be associated with lipid accumulation and calcification. A technique has been developed to isolate them from experimental aneurysms in sheep in which they are known to be plentiful. The matrix vesicles were isolated by differential centrifugation following extraction by hypotonic salt solution. Most of the vesicles were pelleted at 30,000g and fell within the size range of matrix vesicles in situ in the aneurysmal wall. Preliminary characterization of the enzymatic activities indicates that many of these vesicles are formed from cell membranes rather than being derived from lysosomes, mitochondria or endoplasmic reticulum. Morphologically they are similar to matrix vesicles of other mineralizing tissues.
 ...
PMID:Isolation and purification of extracellular matrix vesicles from blood vessels. 162 Jun 91

The kinetics of the 130 kDa monomer obtained by treatment of duck salt gland Na,K-ATPase with C12E8 was compared with that of the membrane-bound enzyme. The shapes of the substrate-velocity curves for the membrane-bound and solubilized forms were quite different: a hyperbolic one for the monomeric Na,K-ATPase and a nonhyperbolic one for the native enzyme. A reaction scheme for ATP hydrolysis based on a comparative analysis of kinetic properties of these two forms is proposed. Experimental evidence in favour of this hypothesis is presented.
 ...
PMID:[Nonhyperbolic kinetics of Na,K-ATPase--a new viewpoint]. 165 44

A membrane-bound nitrate reductase (nitrite:(acceptor) oxidoreductase, EC 1.7.99.4) from the extremely halophilic bacterium Haloferax denitrificans was solubilized by incubating membranes in buffer lacking NaCl and purified by DEAE, hydroxylapatite, and Sepharose 6B gel filtration chromatography. The purified nitrate reductase reduced chlorate and was inhibited by azide and cyanide. Preincubating the enzyme with cyanide increased the extent of inhibition which in turn was intensified when dithionite was present. Although cyanide was a noncompetitive inhibitor with respect to nitrate, nitrate protected against inhibition. The enzyme, as isolated, was composed of two subunits (Mr 116,000 and 60,000) and behaved as a dimer during gel filtration (Mr 380,000). Unlike other halobacterial enzymes, this nitrate reductase was most active, as well as stable, in the absence of salt.
 ...
PMID:Purification and properties of a dissimilatory nitrate reductase from Haloferax denitrificans. 165 31

Previous work has shown that actin binds specifically and saturably to liver membranes stripped of endogenous actin (Tranter, M. P., S. P. Sugrue, and M. A. Schwartz. 1989. J. Cell Biol. 109:2833-2840). Scatchard plots of equilibrium binding data were linear, indicating that binding is not cooperative, as would be expected for F- or G-actin. To determine the state of membrane-bound actin, we have analyzed the binding of F- and G-actin to liver cell membranes. G-actin in low salt depolymerization buffer and EF-actin, a derivative that polymerizes very poorly in solution, bind to liver cell membranes as well as untreated actin in polymerization buffer. Phalloidin-stabilized F-actin binds, but to a lesser extent. The binding of F- and G-actins are mutually competitive and are inhibited by ATP, suggesting that both forms of actin bind to the same sites. For untreated actin in polymerization buffer, the time course of binding is biphasic, with an initial rapid component which is followed by a plateau phase, then a second, slower component. The binding kinetics of pure F-actin and pure G-actin are both monophasic and match the fast and slower components, respectively, of untreated actin. In the reconstituted system, membrane-bound actin does not stain with rhodamine-phalloidin, nor are actin filaments detected by EM. Distinct regions of amorphous material, however, are visible, which stain with an anti-actin antibody. The exact nature of this material has yet to be determined. A model of actin binding is presented.
 ...
PMID:Binding of actin to liver cell membranes: the state of membrane-bound actin. 170 60


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