scholarly journals Inhibitor peptide of mitochondrial proton adenosine triphosphatase. Neutralization of its inhibitory action by calmodulin.

1984 ◽  
Vol 259 (24) ◽  
pp. 15148-15153
Author(s):  
P L Pedersen ◽  
J Hullihen
Keyword(s):  
Inhibitory Action ◽  
Adenosine Triphosphatase ◽  
Inhibitor Peptide

scholarly journals A STUDY OF THE ADENOSINE TRIPHOSPHATASE ACTIVITY OF MYOSIN AND ACTOMYOSIN

1947 ◽  
Vol 30 (5) ◽  
pp. 401-422 ◽  
Author(s):  
W. F. H. M. Mommaerts ◽  
Krikor Seraidarian
Keyword(s):  
Experimental Study ◽  
Low Temperature ◽  
Inorganic Phosphate ◽  
Inhibitory Action ◽  
Adenosine Triphosphatase ◽  
Main Part ◽  
Muscular Activity ◽  
Myosin Atpase ◽  
Contracting Muscle ◽  
Muscular Metabolism

1. An experimental study was made on the adenosine triphosphatase action of crystalline myosin and actomyosin preparations under different conditions. 2. No enzymatic activity was found in the absence of salts. Activation was given by KCl and CaCl2, whereas MgCl2 in the presence of other ions inhibited. 3. The effect of pH is complex. In stabilizing buffers or at low temperature, there are two optima (pH 6.2 to 6.5 and pH 9.2) provided Ca is present. Without Ca only the acid optimum is found. The highest activities are reached in glycine buffer at pH 9.2 in the presence of Ca. 4. The study of the Mg-Ca antagonism revealed that the inhibition due to Mg is fully developed with Mg:Ca ratios less than 1, the inhibition usually exceeding 90 per cent. 5. It is shown that in the muscle the myosin-ATPase is most probably also subjected to the inhibitory action of the Mg ions. 6. From data in the literature it is calculated that the liberation of inorganic phosphate during muscular activity takes place at a rate of at least 0.200 mg. P per mg. myosin per minute. 7. From the results of the present study it is found that the myosin in the muscle can liberate inorganic phosphate from ATP at a rate of at most 0.003 mg. P per mg. myosin per minute. 8. It is concluded therefore that myosin-ATPase cannot be responsible for the liberation of the main part of the phosphate in contracting muscle, and therefore cannot have the rôle in muscular metabolism ascribed to it in recent hypotheses and discussions.

scholarly journals The relationship between biological activity and primary structure of troponin I from white skeletal muscle of the rabbit

1976 ◽  
Vol 153 (2) ◽  
pp. 375-387 ◽  
Author(s):  
H Syska ◽  
J M Wilkinson ◽  
R J A Grand ◽  
S V Perry
Keyword(s):  
Skeletal Muscle ◽  
Adenosine Triphosphatase ◽  
Troponin I ◽  
Complete Sequence ◽  
Mechanisms Of Action ◽  
Inhibitory Peptide ◽  
Active Inhibitor ◽  
Molar Basis ◽  
Inhibitor Peptide ◽  
The Relationship

1. A series of defined peptides which span the complete sequence were produced from troponin I isolated from white skeletal muscle of the rabbit. 2. Two peptides, CF1 (residues 64-133) and CN4 (residues 96-117) inhibited the Mg2+-stimulated adenosine triphosphatase of desensitized actomyosin. This inhibition was potentiated by tropomyosin and the Mg2+-stimulated adenosine triphosphatase of desensitized actomyosin. This inhibition, unlike that of troponin I and peptides derived from it, was not potentiated by tropomyosin. 4. The most active inhibitor, peptide CN4, was 45-75% as effective as troponin I when compared on a molar basis. The inhibitory peptide, CN4, and also whole troponin I were shown by affinity chromatography to interact specifically with actin. 5. A strong interaction with troponin C was demonstrated with peptide CF2 (residues 1-47), from the N-terminal region of troponin I. Somewhat weaker interactions were shown with peptides CN5 (residues 1-21) and with the inhibitory peptide CN4. 6. The significance of these interactions for the mechanisms of action of troponin I is discussed.

Localization of Adenosine Triphosphatase Activity in the Phleom of Nicotiana Tabacum

1972 ◽  
Vol 30 ◽  
pp. 230-231
Author(s):  
James Cronshaw ◽  
Jamison E. Gilder
Keyword(s):  
Plasma Membrane ◽  
Atpase Activity ◽  
Adenosine Triphosphatase ◽  
Higher Plants ◽  
High Surface ◽  
Root Tip ◽  
Animal Cells ◽  
Physiological Processes ◽  
Tip Cells ◽  
Atpase Localization

Adenosine triphosphatase (ATPase) activity has been shown to be associated with numerous physiological processes in both plants and animal cells. Biochemical studies have shown that in higher plants ATPase activity is high in cell wall preparations and is associated with the plasma membrane, nuclei, mitochondria, chloroplasts and lysosomes. However, there have been only a few ATPase localization studies of higher plants at the electron microscope level. Poux (1967) demonstrated ATPase activity associated with most cellular organelles in the protoderm cells of Cucumis roots. Hall (1971) has demonstrated ATPase activity in root tip cells of Zea mays. There was high surface activity largely associated with the plasma membrane and plasmodesmata. ATPase activity was also demonstrated in mitochondria, dictyosomes, endoplasmic reticulum and plastids.

A study to assess the plaque inhibitory action of a newly formulated triclosan toothpaste

2001 ◽  
Vol 28 (1) ◽  
pp. 86-89 ◽  
Author(s):  
J. Moran ◽  
M. Addy ◽  
R. G. Newcombe ◽  
I. Marlow
Keyword(s):  
Inhibitory Action

Reaction of Acetaldehyde with Human Platelets

1992 ◽  
Vol 67 (01) ◽  
pp. 126-130 ◽  
Author(s):  
Olivier Spertini ◽  
Jacques Hauert ◽  
Fedor Bachmann
Keyword(s):  
Platelet Aggregation ◽  
Inhibitory Action ◽  
Ex Vivo ◽  
Platelet Rich Plasma ◽  
Shape Change ◽  
Reaction Medium ◽  
Human Platelets ◽  
Membrane Glycoproteins ◽  
Neutral Ph

SummaryPlatelet function defects observed in chronic alcoholics are not wholly explained by the inhibitory action of ethanol on platelet aggregation; they are not completely reproduced either in vivo by short-term ethanol perfusion into volunteers or in vitro by the addition of ethanol to platelet-rich plasma. As acetaldehyde (AcH) binds to many proteins and impairs cellular activities, we investigated the effect of this early degradation product of ethanol on platelets. AcH formed adducts with human platelets at neutral pH at 37° C which were stable to extensive washing, trichloracetic acid hydrolysis and heating at 100° C, and were not reduced by sodium borohydride. The amount of platelet adducts formed was a function of the incubation time and of the concentration of AcH in the reaction medium. At low AcH concentrations (<0.2 mM), platelet bound AcH was directly proportional to the concentration of AcH in the reaction medium. At higher concentrations (≥0.2 mM), AcH uptake by platelets tended to reach a plateau. The amount of adducts was also proportional to the number of exposures of platelets to pulses of 20 pM AcH.AcH adducts formation severely impaired platelet aggregation and shape change induced by ADP, collagen and thrombin. A positive correlation was established between platelet-bound AcH and inhibition of aggregation.SDS-PAGE analysis of AcH adducts at neutral pH demonstrated the binding of [14C]acetaldehyde to many platelet proteins. AcH adduct formation with membrane glycoproteins, cytoskeleton and enzymes might interfere with several steps of platelet activation and impair platelet aggregation.This in vitro study shows that AcH has a major inhibitory action on platelet aggregation and may account for the prolonged ex vivo inhibition of aggregation observed in chronic alcoholics even in the absence of alcoholemia.

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