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)

1. The effect was studied of local anesthetics (tetracaine, dibucaine, procaine and xylocaine) on the forward and the backward reactions of the calcium pump of skeletal muscle sarcoplasmic reticulum. 2. The inhibition of the rate of calcium uptake, the rate of calcium-dependent ATP splitting and the rate of calcium-dependent ATP-ADP phosphate exchange by sarcoplasmic reticulum in the presence of the above drugs is at least partially due to the inhibition of the phosphoprotein formation from ATP. 3. The rate of the ADP-induced calcium release from sarcoplasmic reticulum and the rate of ATP synthesis driven by the calcium efflux are inhibited on account of a reduction of the phosphoprotein formation by orthophosphate. 4. The phosphorylation of calcium transport ATPase by either ATP or orthophosphate is diminished by the local anesthetics owing to a reduction in the apparent calcium affinity of sarcoplasmic reticulum emmbranes on the outside and on the inside, respectively. 5. The drug-induced calcium efflux from calcium-preloaded sarcoplasmic reticulum vesicles, a reaction not requiring ADP, is probably not mediated by calcium transport ATPase.
Biochim Biophys Acta 1976 Sep 07
PMID:Aspects of the mechanism of action of local anesthetics on the sarcoplasmic reticulum of skeletal muscle. 13 47

Pretreatment of frog skin epithelium homogenates with sodium dodecyl sulphate in the presence of ATP reveals levels of ouabain-sensitive ATPase activity usually higher and occasionally far higher than those required to sustain maximum rates of Na+ transport. This supports the view that Na+ transport involves only a fraction of the epithelial cells.
Biochim Biophys Acta 1976 Sep 21
PMID:On the amount of (Na+ + K+)-ATPase available for transepithelial sodium ion transport in the amphibian skin. 13 48

1. The activities of some membrane-bound enzymes such as adenylate cyclase, Na+ + K+-stimulated adenosine triphosphatase (Na+ + K+-ATPase), Ca2+-stimulated ATPase and Mg2+-stimulated ATPase were examined in heart sarcolemmal fractions from control and cardiomyopathic hamsters at different stages of heart failure. 2. The basal adenylate cyclase activity in sarcolemma from cardiomyopathic animals with early, moderate and late stages of heart failure was not different from the control values whereas the sodium fluoride- and catecholamine-stimulated adenylate cyclase activities were depressed in cardiomyopathic sarcolemma at moderate and late stages. 3. The sarcolemmal Na+ + K+-ATPase activity was decreased and the non-specific phosphatase activity was increased at early, moderate and late stages of heart failure. 4. The sarcolemmal Ca2+-ATPase activity was decreased at moderate and late stages whereas the Mg2+-ATPase activity was decreased at the late stages of heart failure only. 5. A marked decrease was found in calcium binding by heart sarcolemma from cardiomyopathic hamsters at late stages of failure. 6. These results suggest that dramatic sarcolemmal changes are associated with heart failure, and support the view that membrane abnormalities play a crucial role in the development of myocardial dysfunction, cyclase, calcium binding, heart failure, heart membranes, sarcolemmal enzymes.
Clin Sci Mol Med 1976 Sep
PMID:Comparison of heart sarcolemmal enzyme activities in normal and cardiomyopathic (UM-X7.1) hamsters. 13 61

Four cytoplasmic mutants of Saccharomyces cerevisiae showing loss of mitochondrial rutamycin-sensitive ATPase activity but having significant cytochrome oxidase and NADH-cytochrome c reductase have been isolated. Genetic studies indicate the mutations to be closely linked to each other and have been assigned to a new locus, PHO1. The mutations show a low frequency of recombination with the OL12 locus, suggesting a linkage to this marker. They are not, however, linked to the OLI1 locus. Linkage of the ATPase mutations to the OLI2 locus is also indicated by restoration of wild-type diploids by sigma- clones that retain the segment of mitochondrial DNA carrying OLI2. Based on the recombinants issued from crosses of the mutants with a triple drug-resistant strain and an analysis of the resistance markers present in sigma- clones that are effective in restoring a wild-type phenotype, the PHO1 locus has been placed in the segment of DNA located between PAR1 and OLI2.
Eur J Biochem 1976 Sep
PMID:Localization on mitochondrial DNA of mutations leading to a loss of rutamycin-sensitive adenosine triphosphatase. 13 92

An ATPase which strikingly differed from the mitochondrial ATPases of yeast and of animal tissues was obtained when wheat seedling mitochondria, or electron transport particles derived from them, were subjected to ultrasonication and treated with ammonium sulphate. The enzyme which was purified by chromatography on Sephadex G-100 and DEAE-Sephadex (A50) failed to be inactivated as low as 43 000. The enzyme preparation was capable of hydrolysing ADP, in addition to ATP, and several other nucleoside diphosphates and triphosphates. In contrast to the ATPase of animal mitochondria, the activity of the wheat enzyme was almost as insensitive to oligomycin in intact mitochondria as it was after isolation from the organelles.
Eur J Biochem 1976 Sep
PMID:A low-molecular-weight ATPase from wheat-seedling mitochondria. 13 93

A selective deficit in ouabain-sensitive adenosine triphosphatase has been shown in unilaterally obstructed dog kidneys; the deficit correlates inversely with Na+ and K+ excretion following relief of obstruction. It is postulated that the enzymatic defect may play a role in the etiology of postobstructive diuresis.
Invest Urol 1976 Sep
PMID:Etiology of postobstructive diuresis: ouabain-sensitive adenosine triphosphatase deficit and elevated solute excretion in the postobstructed dog kidney. 13 77

A new ATPase electrophoretically and immunologically distinct from the dynein ATPase studied previously has been solublized and purified from sea urchin sperm flagella. This ATPase has properties similar to those of dynein ATPase. Therefore, we propose that the two ATPases be considered as dynein isoenzymes, with previously studied dynein being known as dynein 1, and the newly discovered ATPase as dynein 2. Some physicochemical and enzymatic properties of dynein 2 have been determined. The molecular weight calculated from the sedimentation coefficient (12.3 "/- 1 S) and Stokes radius (12.8 "/- 0.4 nm) is 690,000 +/- 70,000. The molecular weight of the high molecular weight subunit of dynein 2 has been determined to be 325,000 +/- 40,000 by Na dodecyl-SO4-polyacrylamide gel electrophoresis. The enzymatic properties of dynein 1 and dynein 2 are similar in substrate specificity, pH optimum, and Mg2+ requirement for ATPase activity, but they differ in their Michaelis constant and in their dependence of ATPase activity upon salt concentration. Digestion of dynein 2 with trypsin yields an ATPase-containing protein fragment, similar to Fragment A obtained from dynein 1. An antiserum prepared against Fragment A from dynein 1 did not precipitate dynein 2 or inhibit its ATPase activity.
J Biol Chem 1976 Sep 25
PMID:Dynein 2. A new adenosine triphosphatase from sea urchin sperm flagella. 13 96

Rat spermatozoa from the cauda epididymidis were found to have a lower activity of the surface ATPase than the spermatozoa from the caput region. The enzyme from spermatozoa of both regions had the same Michaelis constant (Km) for ATP of 5 X 10(-4) M. It was partly inhibited by ouabain and fluoride, but strongly inhibited by Cu2+, Zn2+,p-chloromercuribenzoate, 8-anilino-1-naphthalenesulphonate Triton X-100, Lubrol-PX, urea, guanidine hydrochloride, sodium dodecyl sulphate and glycerylphosphorylcholine. The enzyme of the spermatozoa from the cauda epididymidis was more sensitive to inhibition by ouabain and fluoride but less sensitive to inhibition by Cu2+ than that of the cells form the caput region. The Arrhenius plot of the temperature dependence of enzymatic activity varied for the cells from the caput and cauda epididymidis. The differences in the enzyme properties of spermatozoa from the two regions of the epididymis suggested that the decline in the activity during epididymal maturation may reflect changes in the lipids and sulphydryl groups of the sperm membrane.
J Reprod Fertil 1976 Sep
PMID:Changes in surface ATPase of rat spermatozoa in transit from the caput to the cauda epididymidis. 13 82

The interaction between paramyosin and myosin has been studied by enzymological methods. Clam adductor paramyosin inhibits the actin-activated, Mg2+-requiring ATPase of both clam adductor and rabbit skeletal muscle myosins. Myosin and paramyosin must be rapidly coprecipitated for this inhibition. Incubation with F-actin in the absence of ATP does not alter this effect. This inhibition follows a hyperbolic function with respect to paramyosin concentration. Slow precipitation by dialysis of myosin and paramyosin together leads to copolymers with actin-activated ATPase equivalent to that of slowly formed myosin filaments. Both kinds of slowly formed filaments have enzymatic properties distinct from those of the rapidly precipitated proteins. Paramyosin is competitive with F-actin for their effects upon myosin. The apparent affinity of myosin for F-actin is markedly reduced by association with paramyosin, but the extrapolated maximal velocity of actomyosin is unaffected. The specificity of this inhibition is strongly suggested by marked quantitative differences between native and cleaved paramyosins. No inhibition of intrinsic myosin ATPase by paramyosin is seen. These studies suggest that at least two types of condition-dependent association between myosin and paramyosin are possible. One class of interactions is associated with enzymic inhibition in rapidly coprecipitated filaments, whereas slowly formed cofilaments exhibit catalytic activity similar to that of identically treat-d myosin and have a characteristic 14.5 nm axial repeat.
Proc Natl Acad Sci U S A 1976 Sep
PMID:Myosin-paramyosin cofilaments: enzymatic interactions with F-actin. 13 57

The N,N'-dicyclohexylcarbodiimide (DCCD)-sensitive latent adenosinetriphosphatase (ATPase) (EC 3.6.1.3; ATP phosphohydrolase) from Mycobacterium phlei has been purified to homogeneity and used to resotre oxidative phosphorylation to detergent-extracted membranes. The phosphorylation was inhibited by DCCD any by tetraphenylboron and valinomycin. The enzyme was solubilized from the membrane vesicles by treatment with cholate followed by extraction with Triton X-100. After partial purification on a sucrose gradient, the enzyme was purified to homogeneity by affinity chromatography on Sepharose coupled to ADP. The DCCD-sensitive latent ATPase of coupling factor from M. phlei consists of two components, the latent ATPase (Bcf4), which is insensitive to DCCD, and an intrinsic membrane component, BCF0. This hydrophobic portion of the DCCD-sensitive ATPase was partially purified on a sucrose gradient after solubilization with detergents from membrane vesicles that had been first depleted of the BCF4 by washing with 0.25 M sucrose. When BCF0 was combined with purified BCF4, the latent ATPase of the resulting complex was sensitive to DCCD. Moreover, like the purified DCCD-sensitive latent ATPase, the combined BCF4 and BCF0 restored coupled phosphorylation to detergent-extracted membranes.
Proc Natl Acad Sci U S A 1976 Sep
PMID:Restoration of oxidative phosphorylation by purified N,N'-dicyclohexylcarbodiimide-sensitive latent adenosinetriphosphatase from Mycobacterium phlei. 13 58


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