Document Detail


A conformational model of the action of general anesthetics at the membrane level. III. Anesthetics and the properties of membrane-bound enzymes: mitochondrial ATPase.
MedLine Citation:
PMID:  158576     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
We have studied the effect of general anesthetics on the kinetic properties of the mitochondrial Mg2+-dependent ATPase. The enzyme is inhibited by anesthetics (alcohols, halotane, pentrane, ketamine) at concentrations of the order of those found to affect lipid-protein interactions. The inhibition appears usually uncompetitive with respect to the substrate, ATP, with a decrease of both Vmax and KM, indicating a possible stabilization of the enzyme-substrate complex. Arrhenius plots of ATPase activity show a striking increase in activation energy below 17-20 degrees C. Anesthetics affect the temperature dependence by increasing the activation energy above the break or abolishing the break whatsoever. An exception is diethyl ether, that induces a decrease in activation energy and a shift of the break to lower temperatures. Anesthetics make the ATPase insensitive to energy transfer inhibitor, oligomycin and dicyclohexyl carbodiimide. At low anesthetic concentration the oligomycin inhibition curve is changed from sigmoidal to hyperbolic, showing a loss of cooperativity in the inhibition.
Authors:
G Lenaz; G Curatola; L Mazzanti; G Parenti-Castelli; L Landi; A M Sechi
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  The Italian journal of biochemistry     Volume:  27     ISSN:  0021-2938     ISO Abbreviation:  Ital. J. Biochem.     Publication Date:    1978 Nov-Dec
Date Detail:
Created Date:  1979-12-18     Completed Date:  1979-12-18     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0376564     Medline TA:  Ital J Biochem     Country:  ITALY    
Other Details:
Languages:  eng     Pagination:  431-49     Citation Subset:  IM    
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MeSH Terms
Descriptor/Qualifier:
Adenosine Triphosphatases / antagonists & inhibitors,  metabolism*
Anesthesia, General
Anesthetics / pharmacology*
Animals
Binding Sites / drug effects
Cattle
Colorimetry
Dicyclohexylcarbodiimide / pharmacology
Humans
Membrane Fluidity / drug effects
Membrane Lipids / metabolism
Membrane Proteins / metabolism
Membranes / drug effects*,  enzymology
Mitochondria, Heart / enzymology
Models, Biological*
Oligomycins / pharmacology
Temperature
Chemical
Reg. No./Substance:
0/Anesthetics; 0/Membrane Lipids; 0/Membrane Proteins; 0/Oligomycins; 538-75-0/Dicyclohexylcarbodiimide; EC 3.6.1.-/Adenosine Triphosphatases

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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