Inhibitory Effect of Vitamin D2 on Adenosine-triphosphatase Activity

Nature ◽  
1966 ◽  
Vol 212 (5058) ◽  
pp. 203-204 ◽  
Author(s):  
V. B. SPIRICHEV ◽  
N. V. BLAZHEVICH
Keyword(s):  
Adenosine Triphosphatase ◽  
Inhibitory Effect ◽  
Vitamin D2 ◽  
Adenosine Triphosphatase Activity

scholarly journals The effect of tropomyosin on the adenosine triphosphatase activity of desensitized actomyosin

1967 ◽  
Vol 105 (3) ◽  
pp. 1235-1243 ◽  
Author(s):  
M. C. Schaub ◽  
S V Perry ◽  
D. J. Hartshorne
Keyword(s):  
Acetic Acid ◽  
Inhibitory Activity ◽  
Adenosine Triphosphatase ◽  
Inhibitory Effect ◽  
Tryptic Digestion ◽  
Prolonged Treatment ◽  
Thiol Groups ◽  
Protein Thiol ◽  
Adenosine Triphosphatase Activity ◽  
Inhibitory Activities

1. Tropomyosin preparations of the Bailey type, and those prepared in the presence of dithiothreitol to prevent oxidation of protein thiol groups, inhibit the Ca2+-activated adenosine triphosphatase (ATPase) of desensitized actomyosin by up to 60%. 2. The inhibitory activity of myofibrillar extracts and tropomyosin survives various agents known to denature proteins but to the action of which tropomyosin is unusually stable, namely heating at 100° and mild tryptic digestion. It is destroyed by prolonged treatment with trypsin. 3. The ethylenedioxybis-(ethyleneamino)tetra-acetic acid (EGTA)-sensitizing factor present in extracts of natural actomyosin and myofibrils could be selectively destroyed, leaving unchanged the inhibitory effect on the Ca2+-activated ATPase. There was no correlation between the EGTA-sensitizing and the Ca2+-activated inhibitory activities of tropomyosin prepared under different conditions. 4. Optimum inhibition was achieved when tropomyosin and the myosin of desensitized actomyosin were present in approximately equimolar proportions. Tropomyosin had no effect on the Ca2+-activated ATPase of myosin measured under similar conditions. 5. Evidence is presented showing that the tropomyosin binds to desensitized actomyosin under the conditions in which the ATPase is inhibited.

scholarly journals THE HISTOCHEMICAL DEMONSTRATION OF ADENOSINE TRIPHOSPHATASE ACTIVITY IN MYOCARDIUM

1964 ◽  
Vol 12 (10) ◽  
pp. 740-743 ◽  
Author(s):  
N. R. NILES ◽  
J. CHAYEN ◽  
G. J. CUNNINGHAM ◽  
LUCILLE BITENSKY
Keyword(s):  
Enzymatic Activity ◽  
Adenosine Triphosphate ◽  
Adenosine Triphosphatase ◽  
Inhibitory Effect ◽  
Histochemical Demonstration ◽  
Human Myocardium ◽  
Phosphate Esters ◽  
Precise Localization ◽  
Adenosine Triphosphatase Activity

Adenosine triphosphatase has been demonstrated histochemically in rat and human myocardium. To obtain its precise localization in discrete bands, apparently corresponding to the concentration of myosin, it was necessary to modify the existing technique to obtain better preservation of unfixed tissue and maximal enzymatic activity. Thus it was necessary to increase the concentration of calcium and to effect the reaction at pH 9.4 after treatment with 2:4-dinitrophenol. The specificity of the reaction was shown by these factors, by testing with phosphate esters other than adenosine triphosphate, and by the inhibitory effect of magnesium.

Effect of aldehyde fixatives on the adenosine phosphatases and ultrastructure of Vitreoscilla

1973 ◽  
Vol 19 (9) ◽  
pp. 1059-1064 ◽  
Author(s):  
Jeffrey C. Burnham ◽  
George J. Hageage Jr.
Keyword(s):  
Enzyme Inhibition ◽  
Microscopic Examination ◽  
Adenosine Triphosphatase ◽  
Osmium Tetroxide ◽  
Electron Microscopic Examination ◽  
Inhibitory Effect ◽  
Electron Microscopic ◽  
Adenosine Triphosphatase Activity ◽  
Enzymes Inhibition ◽  
Adenosine Phosphate

A variety of aldehydes used in electron cytochemistry including glutaraldehyde, glycidaldehyde, acetaldehyde, and methanol-free formaldehyde were examined for their inhibitory effect on the adenosine phosphate hydrolases of Vitreoscilla species. Enzyme inhibition increased with increasing aldehyde concentration. Of the aldehydes tested glycidaldehyde and acetaldehyde were least inhibitory for both adenosine diphosphatase and adenosine triphosphatase activity. Significantly, a 1% concentration of glutaraldehyde inhibited over 80% of the activity of both enzymes. Inhibition by all fixatives was variably decreased by the addition of 8% sucrose. Electron-microscopic examination of Vitreoscilla species fixed with the various aldehydes revealed that both acetaldehyde and glycidaldehyde followed by osmium tetroxide postfixation gave results comparable with glutaraldehyde–osmium tetroxide fixed cells.

scholarly journals The relaxing protein system of striated muscle. Resolution of the troponin complex into inhibitory and calcium ion-sensitizing factors and their relationship to tropomyosin

1969 ◽  
Vol 115 (5) ◽  
pp. 993-1004 ◽  
Author(s):  
M. C. Schaub ◽  
S V Perry
Keyword(s):  
Ionic Strength ◽  
Adenosine Triphosphatase ◽  
Striated Muscle ◽  
Inhibitory Effect ◽  
Inhibitory Factor ◽  
Adenosine Triphosphatase Activity ◽  
Protein System ◽  
Maximum Inhibition ◽  
Troponin Complex ◽  
Low Ionic Strength

1. A method involving isoelectric precipitation and chromatography on SE-Sephadex (sulphoethyl-Sephadex) is described for the preparation of the troponin complex free of tropomyosin from low-ionic-strength extracts of natural actomyosin and myofibrils. 2. Purified troponin complex required tropomyosin to inhibit the Mg2+-stimulated adenosine triphosphatase activity and superprecipitation of desensitized actomyosin in the presence of ethanedioxybis(ethylamine)tetra-acetate. An upper limit of 35000 for the ‘molecular weight’ of the troponin complex was derived from the amounts required to bring about 50% of the maximum inhibition of the Mg2+-stimulated adenosine triphosphatase activity of desensitized actomyosin of known concentration. 3. In the presence of dissociating reagents the troponin complex could be dissociated into inhibitory and Ca2+-sensitizing factors, which could be isolated separately on SE-Sephadex. The inhibitory factor inhibited the Mg2+-stimulated adenosine triphosphatase activity and superprecipitation of desensitized actomyosin independently of the concentration of free Ca2+ in the medium. 4. The Ca2+-sensitizing factor changed its electrophoretic mobility on polyacrylamide gel in the presence of ethanedioxybis(ethylamine)tetra-acetate. It formed a complex with the inhibitory factor at low ionic strength and the original biological activity of the troponin complex could be restored on mixing the inhibitory factor with the Ca2+-sensitizing factor in the ratio of about 3:2. 5. Evidence is presented indicating that the ability of tropomyosin preparations to restore relaxing-protein-system activity to the troponin complex and their inhibitory effect on the Ca2+-stimulated adenosine triphosphatase activity of desensitized actomyosin are two properties of different stability to preparative procedures and tryptic digestion. This suggests that the relaxing protein system of muscle may contain another as yet uncharacterized component.

scholarly journals Environmental CO2 Stimulation of Mitochondrial Adenosine Triphosphatase Activity

1963 ◽  
Vol 238 (2) ◽  
pp. 836-842
Author(s):  
D.D. Fanestil ◽  
A Baird Hastings ◽  
Theodore A. Mahowald
Keyword(s):  
Adenosine Triphosphatase ◽  
Adenosine Triphosphatase Activity ◽  
Stimulation Of
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