Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.6.1.3 (ATPase)
 65,361 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A. laidlawii membrane vesicles are able to accumulate C14-glucose as well as maltose and fructose against the concentration gradient in the absence of exogeneous entergetic sources. Sugar transport is inhibited by anaerobiosis and by the electron transfer inhibitors such as rotenone and amytal, and by proton conductors such as carbonylcyanide-m-chlorophenylhydrazone. Arsenate and dicyclohexylcarbodimide (inhibitor of membrane-bound ATPase) do not inhibit the sugar transport. It is concluded that sugar transport in the membrane vesicles can be driven by the high-energy state of the membrane or the membrane potential.
 ...
PMID:[Basic evidence for the active transport of carbohydrates in the membrane vesicles of Acholeplasma laidlawii cells]. 86 Dec 65

Using specific anti-BiP/Kar2 antibody as the probe, we have developed an efficient purification method of BiP/Kar2 protein from the total cell extract of Saccharomyces cerevisiae. Overproduction of BiP/Kar2 protein was achieved by the cloning of the KAR2 gene on multicopy plasmids and the treatment of cells harboring the cloned KAR2 gene with tunicamycin. Freeze-thaw treatment, hydroxyapatite high pressure liquid chromatography, and ATP-agarose column chromatography of crude extract yielded homogeneous BiP/Kar2 protein (including less than 0.2% of degradative derivative) with a 430-fold purification and 28% recovery. Edman degradation of purified BiP/Kar2 suggests that the mature protein corresponds to a processed product with the removal of a 42-amino acid presequence. It is active as a homodimer and exhibits ATPase activity with a specific activity of 2 pmol/min/micrograms of protein. Protease susceptibility indicated that the ADP form of BiP/Kar2 is more resistant than the ATP form to the chymotrypsin digestion and that BiP/Kar2 required the presence of ATP to avoid the irreversible denaturation. Synthesis of BiP/Kar2 was induced by the inducible expression of an aberrant heterologous protein, yeast killer prepro-signal mouse alpha-amylase fusion protein.
 ...
PMID:Purification and characterization of BiP/Kar2 protein from Saccharomyces cerevisiae. 132 40

1. The present work aims to find a biochemical criterion for evaluating the evolution of sperm according to age through the study of the ATPase activity from the spermatozoa and the acid phosphatase from the seminal plasma of cocks from three different breeds. 2. The optimal parameters of action of the cock semen acid phosphatase and the Ca(2+)-dependent ATPase from the spermatozoa were studied. 3. The substrate specificity of the semen acid phosphatase and its inhibition by tartrate, fluoride, metavanadate, molybdate and Hg2+ were also studied. 4. The two enzymes were determined from the Sussex, Golden Cornish and Plymouth Rock breeds at different ages. 5. The data lead to the conclusion that some properties of bird spermatozoa are less influenced by breed while the acid phosphatase activity, secreted in the ductus deferens is a breed characteristic.
 ...
PMID:Correlations between the activities of semen acid phosphatase and Ca(2+)-dependent ATPase and age in different breeds of cocks. 145 39

The mouse BCM1 (OX45, Blast-1) antigen has been cDNA cloned and sequenced to provide data supporting the view that BCM1, LFA3, and CD2 constitute a subgroup within the Ig superfamily. Mouse BCM1 is widely expressed on leukocytes and is likely to be anchored to the cell surface by a glycosyl-phosphatidylinositol anchor, as is the case for rat and human BCM1 antigen. Genetic linkage studies by recombination and pulse field analysis showed the BCM1 locus (Bcm-1) to be on distal mouse chromosome 1 and to be linked within 1,600 kb to the locus for an ATPase alpha chain gene (Atpa-3). A similar relationship was established between the human BCM1 locus (BCM1) and ATP1A2, and other markers on chromosome 1q. Conservation of genomic organization within a segment of human chromosome 1q and mouse chromosome 1 was demonstrated. A similar situation is seen in the region of the CD2 and LFA3 genes between mouse chromosome 3 and human chromosome 1p. Furthermore, the CD2/LFA3 genes are linked within 580 kb to Atpa-1/ATP1A1 genes to provide a parallel situation to the linkage between Bcm-1/BCM1 and Atpa-3/ATP1A2 on chromosomes 1 (mouse) and 1q (human). Taken together, the data suggest duplication of a chromosome region including the precursors of the genes for BCM1, CD2, and LFA3, and the ATPase genes to give rise to the linkage groups now observed. The duplicated regions may have stayed together on chromosome 1 in the human (with the insertion of a centromere), while in the mouse, the genetic regions are proposed to have become dispersed in the formation of chromosomes 1 and 3. CD2 and LFA3 are more dissimilar in sequence than BCM1 and LFA3, and if the precursors of the CD2 and LFA3 loci formed before the proposed chromosome segment duplication, then a gene encoding a recognizer molecule for BCM1 may exist in linkage with Bcm-1/BCM1 on chromosome 1 (mouse) and 1q (human).
 ...
PMID:Structure, expression, and genetic linkage of the mouse BCM1 (OX45 or Blast-1) antigen. Evidence for genetic duplication giving rise to the BCM1 region on mouse chromosome 1 and the CD2/LFA3 region on mouse chromosome 3. 169 56

The presence of an ATPase on yeast peroxisomal membranes was studied by immunological methods. Western blot analysis of purified peroxisomal membranes from several yeasts revealed distinct cross-reaction with specific antibodies against the F1-part or the beta-subunit of the mitochondrial ATPase of Saccharomyces cerevisiae. This was not due to mitochondrial contamination as was demonstrated by analytical sucrose gradient centrifugation. Protein A-gold labelling carried out on Lowicryl-embedded methanol-grown Hansenula polymorpha using these antibodies did not result in significant staining. However, when organelles isolated from this yeast were successively incubated with antibodies and protein A-gold prior to embedding, specific labelling was observed on both the peroxisomal membrane and the membrane of damaged mitochondria but not on intact mitochondria. Specific labelling of the peroxisomal membrane was confirmed by freeze-fracture immunocytochemistry. In addition to the peroxisomal membrane, the mitochondrial membrane was also labelled in these experiments. Freeze-fracture immunocytochemistry was also successful for the localization of peroxisomal matrix proteins, e.g. alcohol oxidase and dihydroxyacetone synthase, and of mitochondrial membrane proteins, e.g. cytochrome c oxidase.
 ...
PMID:Immunocytochemical demonstration of the peroxisomal ATPase of yeasts. 213 97

The structural basis for Ca2+ transport was examined in vesicles reconstituted with an excess of phospholipid by a cholate dialysis procedure. Unincorporated protein and vesicles with a relatively high protein content were removed by sucrose density centrifugation (3-12%), leaving a fraction of lipid-rich vesicles (lipid to protein weight ratio 800-900:1) with a high coupling ratio (1.0) and transport capacity (25 mumol/mg protein, after Ca-phosphate loading). Freeze-fracture analysis showed that the reconstituted vesicles had a remarkably narrow size distribution (diameter 794 +/- 77 A (S.D.], suitable for stereological analysis. Intramembranous particles were dispersed and occurred with a low frequency in the fractured shells, also before sucrose fractionation. It was calculated that the number of intramembranous particles corresponded to the number of Ca2(+)-ATPase polypeptide/vesicle. A ratio of unity between particles and polypeptide chains was also obtained from the density of particle distribution on flat surfaces of fused vesicles, prepared by sucrose fractionation. The size of the particles formed a broad distribution, having a peak value around 60-67 A, both in the reconstituted preparation and sarcoplasmic reticulum vesicles. No evidence for protein-protein interactions was found in chemical cross-linking experiments. It is concluded that the intramembranous particles in the reconstituted preparations are referable to monomeric Ca2(+)-ATPase which is capable of transporting Ca2+ inside the vesicles. The implications of the observations for the associational state of Ca2(+)-ATPase at high protein concentration are considered in relation to previous ultrastructural investigations of membranous Ca2(+)-ATPase in native and two-dimensional-crystalline forms.
 ...
PMID:Monomeric state and Ca2+ transport by sarcoplasmic reticulum Ca2(+)-ATPase, reconstituted with an excess of phospholipid. 214 57

Equilibrium and kinetic aspects of Triton X-100 adsorption onto hydrophobic Bio-Beads SM2 were investigated in detail using the batch procedure originally described by Holloway, P.W. (1973) Anal. Biochem. 53, 304-308. The results demonstrated the importance of the initial detergent concentration, the amount of beads, the commercial source of the detergent, the temperature and the presence of phospholipids in determining the rates of Triton X-100 adsorption onto Bio-Beads. One of the main findings was that Bio-Beads allowed the almost complete removal of Triton X-100, whatever the initial experimental conditions. It was shown that monomeric as well as micellar detergent could be adsorbed and that a key factor in determining the rate of detergent removal was the availability of the free bead surface. Rates of detergent removal were found to be linearly related to the amount of beads even for bead concentrations above those sufficient to remove all the detergent initially present. Adsorptive capacity of phospholipids onto Bio-Beads SM2 was also analyzed and found to be much smaller (2 mg lipid per g of wet beads) than that of Triton X-100 (185 mg TX 100 per g of wet beads). A more general aspect of this work was that the use of Bio-Beads SM2 provided a convenient way for varying and controlling the time course of Triton X-100 removal. The method was further extended to the formation of liposomes from phospholipid-Triton X-100 micelles and the size of the liposomes was found to be critically dependent upon the rate of detergent removal. A general procedure was described to prepare homogeneous populations of vesicles. Freeze-fracture electron microscopy and permeability studies indicated that the liposomes thus obtained were unilamellar, relatively large and impermeable. Noteworthy, this new procedure was shown to be well suited for the reconstitution of different membrane transport proteins such as bacteriorhodopsin, Ca2(+)-ATPase and H(+)-ATPase.
 ...
PMID:A systematic study of liposome and proteoliposome reconstitution involving Bio-Bead-mediated Triton X-100 removal. 236 77

The effects of a high dose of acetylcholine (ACh) on oxygen consumption (VO2) and changes in phosphorus energy metabolites during secretion were studied in isolated perfused mandibular gland of rats at 24 degrees C. Sugar phosphates (SP), Pi, phosphocreatine (PCr), and ATP were identified by phosphorus-31 nuclear magnetic resonance spectroscopy. One micromole ACh induced a tachyphylactic secretory response, a persistently elevated VO2, and decreased PCr and ATP; 1 mM ACh caused an initial burst of secretion that was followed by suppression of secretion and a rapid increase in the VO2 to the same level as that with 1 microM ACh. These findings indicate a dissociation between secretion and VO2. During stimulation with 1 mM ACh, the level of PCr first decreased and then partially recovered, but the level of ATP continued to decrease and the levels of Pi and SP increased markedly. These findings suggest compartmentalization of creatine phosphokinase (CPK) systems and the possibility that a high concentration of ACh interferes with the transport of PCr between one CPK system near adenosinetriphosphatase and another system near mitochondria in acinar cells.
 ...
PMID:Dissociation of fluid secretion and energy supply in rat mandibular gland by high dose of ACh. 283 65

The vanadate-sensitive ATPase of Streptococcus faecalis, purified to homogeneity, was reconstituted into soybean phospholipid vesicles in a functional state. Freeze-fracture electron micrographs revealed a relatively uniform population of unilamellar liposomes of 50-100 nm in diameter, with particles protruding from both fracture faces. Transport studies with 42K+ and with a K+-selective electrode showed that the ATP-ase catalyzes electrogenic potassium extrusion in proteoliposomes. The following parameters for potassium transport in the reconstituted system were determined: K+/ATP stoichiometry = 1, Km for potassium = 1.4 mM, Vmax = 0.1 mumol/min/mg. The ATPase could be activated by an electrical membrane potential, vesicle interior positive. This ATPase thus appears to function as a potential regulated, ATP-driven pump that serves in electrogenic potassium accumulation by the bacterial cell.
 ...
PMID:The vanadate-sensitive ATPase of Streptococcus faecalis pumps potassium in a reconstituted system. 293 40

These studies addressed the question of the in vivo distribution of rat brain hexokinase (HK), and whether physiologically relevant changes in the glycolytic rate are accompanied by changes in the distribution of HK. Homogenates of fresh tissue showed only 11-15% of the overt (assayable without added detergent) HK to be soluble (found in high-speed centrifugation supernatant fractions) when homogenization was begun within 15-20 s of sacrifice. Freeze-blown rat brain tissue also was used, coupled with a new technique wherein it was homogenized as it thawed in a buffered sucrose solution containing 1 mM EDTA. In tissue sampled 15 min (anesthetized) or 60 min (waking) after ip Nembutal injection (40 mg/kg), 23% of the overt HK and 79% of the total lactate dehydrogenase were soluble. The average phosphocreatine content of these and similar homogenates had decreased only 23% from in vivo levels, while ATP had decreased by 65%, due to the combined effects of a high level of endogenous ATPase, chelation of Mg2+ by EDTA, and the greater stability of Mg-ATP2- relative to Mg-ADP1-. These data indicated that the tissue experienced, at most, the equivalent of 6 s of complete ischemia prior to the completion of homogenization. Synaptosomes derived from rat and chicken cerebra were incubated at 37 degrees C in a physiological salt solution containing 10 mM glucose. Addition of veratridine has been shown to stimulate glycolysis and oxidative phosphorylation two- to threefold (H. T. Kyriazi and R. E. Basford (1986) J. Neurochem., in press), but did not alter the HK distribution, as 21% was found in the supernatant fractions of both control and veratridine-stimulated synaptosomes treated with digitonin. These results indicate that in brain tissue, large net movements of HK on and off the outer mitochondrial membrane do not occur, and thus play no role in the regulation of glycolysis.
 ...
PMID:An examination of the in vivo distribution of brain hexokinase between the cytosol and the outer mitochondrial membrane. 294 9


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