Tween-20 activates and solubilizes the mitochondrial membrane-bound, calmodulin dependent NAD+ finase of Avena sativa L.
Among different treatments assayed, a mix of a nonionic detergent (5% Tween-20) with 0.5 m NaCl was found to solubilize a large part of the calmodulin-dependent NAD+ kinase bound to the inner mitochondrial membrane. It also stimulated its activity by increasing 7 times the maximal velocity. Activity stimulation was also observed with phosphatidylcholine, phosphatidylethanolamine and with reductants (HSO3 and DTT). This solubilized NAD+ kinase and the calmodulin-dependent cytosoluble isoform displayed distinct molecular masses, as well as different kinetic parameters. We propose that solubilization of membrane-bound NAD+ kinase could occur in vivo in Avena sativa and could generate a soluble isoform.
Pou De Crescenzo
M A
MA
Equipe de Biochimie et de Biologie Moléculaire, UFR Sciences, Université d'Angers, 2 Boulevard Lavoisier, 49 045 Angers Cedex 01, France.
Gallais
S
S
Léon
A
A
Laval-Martin
D L
DL
D018554:Avena / Q000201:enzymology*; D002118:Calcium / Q000494:pharmacology; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000378:metabolism; D002147:Calmodulin / Q000494:pharmacology; D002148:Calmodulin-Binding Proteins / Q000494:pharmacology; D002458:Cell Fractionation; D007700:Kinetics; D008565:Membrane Proteins; D008928:Mitochondria / Q000378:metabolism; D010084:Oxidation-Reduction; D017853:Phosphotransferases (Alcohol Group Acceptor) / Q000187:drug effects / Q000378:metabolism*; D011136:Polysorbates / Q000494:pharmacology*; D012639:Seeds; D012965:Sodium Chloride / Q000494:pharmacology; D013501:Surface-Active Agents / Q000494:pharmacology
D002147:Calmodulin; D002148:Calmodulin-Binding Proteins; D008565:Membrane Proteins; D011136:Polysorbates; D013501:Surface-Active Agents; D012965:Sodium Chloride; D017853:Phosphotransferases (Alcohol Group Acceptor); C021844:NAD kinase; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D002118:Calcium