Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.6.3.1 (Mg2+-ATPase)
 1,484 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Membrane vesicles of Escherichia coli prepared by osmotic lysis of lysozyme ethylenediaminetetracetate (EDTA) spheroplasts have approximately 60% of the total membrane-bound reduced nicotinamide adenine dinucleotide (NADH) dehydrogenase (ED 1.6.99.3) and Mg2+-adenosine triphosphatase (ATPase) (EC 3.6.1.3) activities exposed on the outer surface of the inner membrane. Absorption of these vesicles with antiserum prepared against the purified soluble Mg2+-ATPase resulted in agglutination of approximately 95% of the inner membrane vesicles, as determined by dehydrogenase activity, and about 50% of the total membrane protein. The unagglutinated vesicles lacked all dehydrogenase activity and may consist of outer membrane. Lysozyme-EDTA vesicles actively transported calcium ion, using either NADH or adenosine 5'-triphosphate (ATP) as energy source. However, neither D-lactate nor reduced phenazine methosulfate energized calcium uptake, suggesting that the observed calcium uptake was not due to a small population of everted vesicles. Transport of calcium driven by either NADH or ATP was inhibited by simultaneous addition of D-lactate or reduced phenazine methosulfate. Proline transport driven by D-lactate oxidation was inhibited by either NADH oxidation or ATP hydrolysis. These results suggest that the portion of the total population of vesicles capable of active transport, i.e., the inner membrane vesicles, are functionally a homogeneous population but cannot be categorized as either right-side-out or everted, since activities normally associated with only one side of the inner membrane can be found on both sides of the membrane of these vesicles. Moreover, the data indicate that oxidation of NADH or hydrolysis of ATP by externally localized NADH dehydrogenase or Mg2+-ATPase establishes a protonmotive force of the opposite polarity from that established through D-lactate oxidation.
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PMID:Functional mosaicism of membrane proteins in vesicles of Escherichia coli. 19 Feb 12

Ultrastructural morphometric and biochemical studies were conducted on hepatic mitochondria from control rats and rats treated in vivo with arsenate to examine changes in interrelationships between mitochondrial structure and biochemical functions. Morphometric analysis disclosed an over-all 1.2-fold increase in the relative mitochondrial volume density and 1.4-fold increase in the surface density of the inner mitochondrial membrane of arsenate-exposed rats. These structural changes were associated with a 1.5-fold increase in 14C-leucine incorporation into all mitochondrial proteins, which was primarily associated with the acid-insoluble membranous fraction. Mitochondria from arsenate-treated rats showed a marked disruption of normal conformational behavior with depression of nicotinamide adenine dinucleotide (NAD)-linked substrate oxidation and a resulting in vivo increase in the mitochondrial [NAD] to [NADH] ratio. Observed changes in mitochondrial membranes from arsenate exposure also resulted in 1.5- to 2-fold increases in the specific activities of the membrane marker enzymes monoamine oxidase, cytochrome oxidase, and Mg2+-ATPase. Activity of malate dehydrogenase, which is localized in the mitochondrial matrix, was unchanged. The results of this study demonstrate a positive quantitative in vivo correlation between mitochondrial structure and function and indicate a marked dependency upon membrane integrity for normal maintenance of the specific biologic activities performed by this organelle in vivo.
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PMID:Studies of hepatic mitochondrial structure and function: morphometric and biochemical evaluation of in vivo perturbation by arsenate. 49 44

The effect of regucalcin, a calcium-binding protein isolated from rat liver cytosol, on Ca2+-adenosine triphosphatase (ATPase) activity in hepatic microsomes was investigated. Mg2+-ATPase activity was clearly increased by the presence of 50 microM Ca2+. Regucalcin (1.0-4.0 microM) caused a remarkable elevation (about 3-fold) of Ca2+-ATPase activity. Also, Mg2+-ATPase activity was increased (about 1.6-fold) by the presence of regucalcin (2.0 and 4.0 microM). Guanosine-5'-O-(3-thiotriphosphate) (GTPrs; 10(-5) and 10(-4) M) and nicotinamide adenine dinucleotide phosphate oxidized form (NADP+; 10(-5) to 10(-3) M) or reduced form (NADPH; 10(-4) and 10(-3) M) significantly increased Ca2+-ATPase activity. These increases were not enhanced by the presence of regucalcin (2.0 microM). Of various metal ions, a comparatively low concentration of V5+ (10(-5) M) or Cd2+ (10(-6) M) significantly increased Ca2+-ATPase activity, while Hg2+, Zn2+, Cu2+ and Mn2+ did not have such an effect. Regucalcin (2.0 microM) did not enhance the effect of V5+ and Cd2+ on Ca2+-ATPase activity. The present finding, that regucalcin activates hepatic microsomal Ca2+-ATPase, suggests a cell physiological role of regucalcin as an activator in the microsomal Ca2+-pump activity. This action of regucalcin may not be influenced by other regulators.
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PMID:Activation of hepatic microsomal Ca2+-adenosine triphosphatase by calcium-binding protein regucalcin. 252 22

Activity of transport ATPases was studied in erythrocyte membranes and synaptosomal fraction of cervical department of spinal cord obtained from rats in dynamics of botulinic C intoxication Na+, K+-ATPase was inhibited by the competitive type in the synaptosomal brain fraction at the preclinical period of intoxication and by the noncompetitive type at the step of skeletal muscle paresis. In erythrocyte membranes activity of Na+, K+-ATPase was inhibited by the mixed type at the preclinical period of intoxication and the enzymatic activity was inhibited by the noncompetitive type at the step of skeletal muscle paresis. The Na+, K+-ATPase from biological membranes was reactivated by unithiol and nicotinamide in dynamics of intoxication. The toxin was shown to activate Mg2+-ATPase in brain synaptosomal fraction.
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PMID:[Effect of botulinum toxin on the activity of transport ATPases in biological membranes]. 298 43