Effect of (auto)phosphorylation on the kinetic behavior of the Ca2+/calmodulin-dependent protein kinase II from horse brain.
After extraction and purification, the kinetic behavior of the Ca(2+)/calmodulin-dependent protein kinase II (CaM kinase II) from horse brain was investigated as a function of ATP and a synthetic substrate, syntide-2. Both phospho- and dephospho- forms of the enzyme obey a bi-bi random mechanism. The K(M)s for ATP (K(M,ATP)) and syntide-2 (K(M,syntide-2)) were determined as equal to 80 and 30 microM, respectively. However, the maximum reaction yield is decreased by 50% when the enzyme is (auto)phosphorylated. In addition, this phosphorylated form of the enzyme leads to the formation of a totally Ca(2+)-independent state of activity.
Colavizza
Michel
M
UPRESA no 6022 du CNRS, Génie Enzymatique et Cellulaire, BP 20529, Université de Compiègne, 60205 Compiègne cedex, France.
Hervagault
Jean-François
JF
D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D001345:Autoradiography; D001921:Brain / Q000201:enzymology*; D002118:Calcium / Q000378:metabolism; D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000302:isolation & purification / Q000378:metabolism*; D006736:Horses; D036341:Intercellular Signaling Peptides and Proteins; D007700:Kinetics; D008970:Molecular Weight; D010455:Peptides / Q000378:metabolism; D010766:Phosphorylation; D013379:Substrate Specificity
D036341:Intercellular Signaling Peptides and Proteins; D010455:Peptides; C063391:syntide-2; D000255:Adenosine Triphosphate; D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D002118:Calcium