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

The interaction of ruthenium red, [(NH3)5Ru-O-Ru(NH3)4-O-Ru(NH3)5]Cl6.4H2O, with various Ca2(+)-binding proteins was studied. Ruthenium red inhibited Ca2+ binding to the sarcoplasmic reticulum protein, calsequestrin, immobilized on Sepharose 4B. Furthermore, ruthenium red bound to calsequestrin with high affinity (Kd = 0.7 microM; Bmax = 218 nmol/mg protein). The dye stained calsequestrin in sodium dodecyl sulfate-polyacrylamide gels or on nitrocellulose paper and was displaced by Ca2+ (Ki = 1.4 mM). The specificity of ruthenium red staining of several Ca2(+)-binding proteins was investigated by comparison with two other detection methods, 45Ca2+ autoradiography and the Stains-all reaction. Ruthenium red bound to the same proteins detected by the 45Ca2+ overlay technique. Ruthenium red stained both the erythrocyte Band 3 anion transporter and the Ca2(+)-ATPase of skeletal muscle sarcoplasmic reticulum. Ruthenium red also stained the EF hand conformation Ca2(+)-binding proteins, calmodulin, troponin C, and S-100. This inorganic dye provides a simple, rapid method for detecting various types of Ca2(+)-binding proteins following electrophoresis.
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PMID:Interaction of ruthenium red with Ca2(+)-binding proteins. 169 45

Incubation of human red blood cell membranes (white ghosts) with N-acetyl-p-benzoquinone imine (NAPQI), a toxic metabolite of acetaminophen, or with either an arylating or an oxidizing analog of NAPQI, resulted in the inhibition of membrane ion transporting systems and the modification of cytoskeletal proteins. NAPQI and 2,6-dimethyl-NAPQI, which primarily arylates protein thiols, inhibited the calmodulin-activated Ca pump ATPase activity, the basal (calmodulin-independent) Ca pump ATPase activity and the Na,K pump ATPase activity. In contrast, 3,5-dimethyl-NAPQI, which primarily oxidizes protein thiols, caused selective inhibition of the calmodulin-activated Ca pump ATPase activity. Sodium dodecyl sulfate gel electrophoresis of red blood cell (RBC) membrane proteins revealed that NAPQI and 2,6-dimethyl-NAPQI, but not 3,5-dimethyl-NAPQI, decreased the intensity of band 3 corresponding to the anion transporter, whereas NAPQI as well as 2,6-dimethyl-NAPQI, and to a lesser extent 3,5-dimethyl-NAPQI, caused a decrease of cytoskeletal protein bands, including spectrin, actin, and bands 4.1 and 4.2. These modifications were associated with increased formation of high molecular weight protein aggregates that did not enter the gel. Treatment of 3,5-dimethyl-NAPQI-exposed ghosts with the reducing agent dithiothreitol (DTT), resulted in the recovery of the affected cytoskeletal protein bands. Conversely, the modifications caused by NAPQI and 2,6-dimethyl-NAPQI were only partially reversed by DTT treatment. Taken together our results suggest that NAPQI and its two analogs modified ion transporting systems and cytoskeletal proteins by reacting with protein thiols. Both oxidation and arylation of protein thiols can alter the functional properties of important RBC membrane proteins. Of the two reactions, arylation appeared to be the less specific and more damaging event.
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PMID:Differential effects of arylating and oxidizing analogs of N-acetyl-p-benzoquinoneimine on red blood cell membrane proteins. 214 23

A well-characterized chicken osteoclast plasma membrane vesicle preparation manifested Mg2(+)-dependent ATP hydrolyzing activity of 0.213 mumol inorganic phosphate released per mg protein per minute (n = 7). The Mg2+ dependence showed a high-affinity component with a KMg of 1.293 microM and Vmax of 0.063 mumol Pi per mg protein per minute, and a low-affinity component with a KMg of 297.6 microM and a Vmax of 0.232 mumol Pi per mg protein per minute. The Mg2(+)-ATPase activity was inhibited by N,N'-dicyclohexylcarbodiimide (DCCD, 0.2 mM, 50.7%), N-ethylmaleimide (0.5 mM, 34.6%), nolinium bromide (1 mM, 29.9%), 4,4'-diisothiocyano-2,2'-stilbene sulfonic acid (DIDS, 1 mM, 45.1%), and p-chloromercuribenzoic acid (PCMB, 0.1 mM, 33.8%). Sodium orthovanadate (Na3 VO4) at 1 microM had no effect but caused 29.5% inhibition at 1 mM. Na+ could substitute for K+ without loss of activity, NO3- caused 19.5% inhibition when substituted for Cl-, and acetate replacement of Cl- resulted in 36.4% stimulation of Mg2(+)-ATPase. ATP, GTP, ITP, CTP, and ADP were all hydrolyzed effectively. DCCD (0.2 mM), NEM (0.5 mM), nolinium bromide (1 mM), and DIDS (50 microM) almost completely abolished proton transport as measured spectrofluorometrically by acridine orange quenching. Na3 VO4 (1 mM) had no effect, and duramycin (80 micrograms/ml) inhibited transport 52.7%. K+ replacement of Na+ caused a 79.2% increase in initial proton transport rate. NO3- and acetate substitution of Cl- resulted in a 46.1 and 55.7% decrease in transport, respectively. ATP supports transport far more effectively than the other nucleotides tested. ADP was ineffective. Experiments using the potassium ionophore, valinomycin, indicated that the proton pump functions electrogenically, with Cl- most likely cotransported by an anion transporter. The proton pump also seems to have at least one anion-sensitive site, elucidated by experiments in the presence of NO3- and Cl-.
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PMID:Biochemical characterization of an electrogenic vacuolar proton pump in purified chicken osteoclast plasma membrane vesicles. 216 21

The interaction between membrane proteins and cytoplasmic structural proteins is thought to be one mechanism for maintaining the spatial order of proteins within functional domains on the plasma membrane. Such interactions have been characterized extensively in the human erythrocyte, where a dense, cytoplasmic matrix of proteins comprised mainly of spectrin and actin, is attached through a linker protein, ankyrin, to the anion transporter (Band 3). In several nonerythroid cell types, including neurons, exocrine cells and polarized epithelial cells homologues of ankyrin and spectrin (fodrin) are localized in specific membrane domains. Although these results suggest a functional linkage between ankyrin and fodrin and integral membrane proteins in the maintenance of membrane domains in nonerythroid cells, there has been little direct evidence of specific molecular interactions. Using a direct biological and chemical approach, we show here that ankyrin binds to the ubiquitous (Na+ + K+)ATPase, which has an asymmetrical distribution in polarized cells.
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PMID:Ankyrin binding to (Na+ + K+)ATPase and implications for the organization of membrane domains in polarized cells. 303 71

Contrasting observations exist which indicate that in plants the fluorescent dye lucifer yellow CH (LYCH) either can be used as a tracer for endocytosis or as a substrate for an anion transporter located at the vacuolar membrane. In addition, LYCH as a disulphonated substance may represent an analogue of sulphonated or sulfated natural compounds like some flavonoids. We performed uptake experiments with LYCH into isolated rye vacuoles and observed saturable (Km = 0.3-0.6 mM) vacuolar transport and accumulation of the dye against the concentration gradient only when MgATP was present. GTP and, to a low extent, UTP could substitute for ATP, while the non-hydrolysable ATP analogue AMP-PNP did not drive LYCH uptake. Vanadate and probenecid, the latter substance is known to inhibit organic anion transport at the liver canalicular membrane, both strongly decreased the vacuolar uptake of LYCH, while bafilomycin A1, a specific inhibitor of the vacuolar H+-ATPase, had no effect. Together with the fact that abolishment of the delta pH via CCCP had only a weak influence on LYCH accumulation, our results indicate that this compound is taken up into rye vacuoles by a directly energized process. Uptake of LYCH was strongly inhibited by other sulfated compounds including sulfobromophthalein and the flavones apigenin 7,4'-disulfate and luteolin 7,4'-disulfate arguing for the presence of a vacuolar transporter for structurally different sulphonated or sulfated compounds. Glucuronates like the rye-specific flavone luteolin 7-O-diglucuronide also strongly decreased uptake of the dye, whereas only a weak effect was observed in the presence of glutathione and a glutathione conjugate, suggesting that LYCH uptake is not mediated via the vacuolar glutathione conjugate pump.
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PMID:Transport of lucifer yellow CH into plant vacuoles--evidence for direct energization of a sulphonated substance and implications for the design of new molecular probes. 945 May 55

An understanding of the action of many drugs requires a knowledge of how the drug reaches the site of action in a cell. A detailed knowledge of the structure and function of cell membranes is often required to understand the transport of drugs across the plasma membrane. To obtain this information proteins must be isolated. The isolation and characterisation of cell membrane proteins usually requires the solubilisation of the membrane and a method of separation of the various membrane proteins and glycoproteins. The starting point for such an investigation is the choice of a suitable surfactant (detergent) to solubilise the membrane. This review considers the range of surfactants that are available for membrane solubilisation, how surfactants interact with membranes, the part they play in the separation of integral membrane proteins and in the reconstitution of membrane proteins for functional studies. The solubilisation of specific membrane proteins and glycoproteins including the human erythrocyte anion transporter, mitochondrial porin, sarcoplasmic reticulum Ca(2+)-ATPase, the ATPase-active multidrug transporter P-glycoprotein, bacteriorhodopsin and rhodopsin are also discussed.
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PMID:Surfactants in membrane solubilisation. 1020 10

Local anaesthetics, in addition to anaesthesia, induce the synthesis of heat shock proteins (HSPs), sensitize cells to hyperthermia, and increase the aggregation of nuclear proteins during heat shock. Anaesthetics are membrane active agents, and anaesthesia appears to be due to altered ion channel activity; however, the direct effect of heat shock is protein denaturation. These observations suggest that local anaesthetics may sensitize cells to hyperthermia by interacting with and destabilizing membrane proteins such that protein denaturation is increased. It is shown, using differential scanning calorimetry (DSC), that the local anaesthetics procaine, lidocaine, tetracaine and dibucaine destabilize the transmembrane domains of the Ca2+ -ATPase of sarcoplasmic reticulum and the band III anion transporter of red blood cells. The transmembrane domain of the Ca2+ -ATPase has a transition temperature (Tm) of denaturation of 61 degrees C which is decreased, for example, to 53 degrees C by 15 mM lidocaine. The degree of destabilization (deltaTm) by each anaesthetic is proportional to the lipid to water partition coefficient, and the increased sensitization by anaesthetics with larger partition coefficients and at higher pH suggests that the uncharged forms of the anaesthetics are responsible for destabilization. A Hill analysis of deltaTm for the Ca2+ -ATPase as a function of the concentration of anaesthetic in water gives dissociation constants (Kd) on the order of 10(-4) M, if binding occurs directly from the aqueous phase. This demonstrates moderate affinity binding. However, dissociation constants of 1-3 M are obtained, if binding occurs through the lipid phase, which demonstrates low affinity binding. Thus, the interaction of local anaesthetics with the Ca2+ -ATPase may be moderately specific or non-specific depending on the mechanism of interaction. The observation that local anaesthetics also destabilize the transmembrane domain of the band III protein of erythrocytes suggests that destabilization of transmembrane proteins is a general property of anaesthetics, which is at least in part a mechanism of sensitization to hyperthermia.
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PMID:Thermal destabilization of transmembrane proteins by local anaesthetics. 1066 13

cMOAT encodes an ATPase within the family of cMOAT/MRP ATPases that functions as an ATP dependent, multispecific anion transporter within the canalicular surface of hepatocytes that has pharmacologic significance. We describe here the cloning of a murine cMOAT cDNA isolated from mouse liver. The open reading frame of this cDNA incorporates 4627 nucleotides encoding 1309 amino acids with 77.5% and 86.7% identity with the human and rat encoded amino acids, respectively. Northern blotting showed that the expression of cMOAT mRNA occurs primarily in mouse liver in the form of two variants with approximately 5.6 and 7.8 kb of sequence each. cMOAT mRNA was also detected in mouse kidney at a low level but was not detected in other mouse organs or tumors except the Hep 1-6 murine hepatoma where expression was also in the form of the same two mRNA variants.
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PMID:Molecular cloning of the murine cMOAT ATPase. 1100 24

Pendrin is an anion transporter encoded by the PDS/Pds gene. In humans, mutations in PDS cause the genetic disorder Pendred syndrome, which is associated with deafness and goiter. Previous studies have shown that this gene has a relatively restricted pattern of expression, with PDS/Pds mRNA detected only in the thyroid, inner ear, and kidney. The present study examined the distribution and function of pendrin in the mammalian kidney. Immunolocalization studies were performed using anti-pendrin polyclonal and monoclonal antibodies. Labeling was detected on the apical surface of a subpopulation of cells within the cortical collecting ducts (CCDs) that also express the H(+)-ATPase but not aquaporin-2, indicating that pendrin is present in intercalated cells of the CCD. Furthermore, pendrin was detected exclusively within the subpopulation of intercalated cells that express the H(+)-ATPase but not the anion exchanger 1 (AE1) and that are thought to mediate bicarbonate secretion. The same distribution of pendrin was observed in mouse, rat, and human kidney. However, pendrin was not detected in kidneys from a Pds-knockout mouse. Perfused CCD tubules isolated from alkali-loaded wild-type mice secreted bicarbonate, whereas tubules from alkali-loaded Pds-knockout mice failed to secrete bicarbonate. Together, these studies indicate that pendrin is an apical anion transporter in intercalated cells of CCDs and has an essential role in renal bicarbonate secretion.
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PMID:Pendrin, encoded by the Pendred syndrome gene, resides in the apical region of renal intercalated cells and mediates bicarbonate secretion. 1127 45

In both bacteria and archaea, molybdate is transported by an ABC-type transporter comprising three proteins, ModA (periplasmic binding protein), ModB (membrane protein) and ModC, the ATPase. The modABC operon expression is controlled by ModE-Mo. In the absence of the high-affinity molybdate transporter, molybdate is also transported by another ABC transporter which transports sulfate/thiosulfate as well as by a nonspecific anion transporter. Comparative analysis of the molybdate transport proteins in various bacteria and archaea is the focus of this review.
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PMID:Molybdate transport. 1142 Dec 78


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