Biomaterial Database

Autoactivation of calmodulin-dependent protein kinase II by autophosphorylation. 1991

T Katoh, and H Fujisawa

Department of Biochemistry, Asahikawa Medical College, Japan.

Autophosphorylation of calmodulin (CaM)-dependent protein kinase II (CaM-kinase II) under limiting conditions (2 microM ATP) decreased progressively with increasing concentrations of a substrate, Pro-Leu-Ala-Arg-Thr-Leu-Ser-Val-Ala-Gly-Leu-Pro-Gly-Lys-Lys (syntide-2), suggesting a competition between the substrate and the autophosphorylation site(s) of the enzyme. The rate and extent of the generation of Ca2+/CaM-independent activity of the enzyme by autophosphorylation were also decreased by the presence of syntide-2. The syntide-2 phosphorylation in the presence of Ca2+/CaM under the limiting conditions reached a steady state, after a lag, when the Ca2+/CaM-independent activity reached a plateau. A linear relationship was observed between the activities in the presence and absence of Ca2+/CaM of the enzyme which had undergone various degrees of autophosphorylation, and the extrapolation of activity in the absence of Ca2+/CaM to zero gave 15-20% of the maximum activity. The steady-state rate of syntide-2 phosphorylation in the presence of Ca2+/CaM by the enzyme that had not undergone prior autophosphorylation was decreased by high concentrations of syntide-2 which suppressed autophosphorylation as well as the generation of Ca2+/CaM-independent activity. These results suggest that although the nonautophosphorylated enzyme possesses a basal low level of Ca2+/CaM-dependent activity, autophosphorylation is required for full activation.

UI	MeSH Term	Description	Entries
D010455	Peptides	Members of the class of compounds composed of AMINO ACIDS joined together by peptide bonds between adjacent amino acids into linear, branched or cyclical structures. OLIGOPEPTIDES are composed of approximately 2-12 amino acids. Polypeptides are composed of approximately 13 or more amino acids. PROTEINS are considered to be larger versions of peptides that can form into complex structures such as ENZYMES and RECEPTORS.	Peptide,Polypeptide,Polypeptides
D010766	Phosphorylation	The introduction of a phosphoryl group into a compound through the formation of an ester bond between the compound and a phosphorus moiety.	Phosphorylations
D011494	Protein Kinases	A family of enzymes that catalyze the conversion of ATP and a protein to ADP and a phosphoprotein.	Protein Kinase,Kinase, Protein,Kinases, Protein
D002118	Calcium	A basic element found in nearly all tissues. It is a member of the alkaline earth family of metals with the atomic symbol Ca, atomic number 20, and atomic weight 40. Calcium is the most abundant mineral in the body and combines with phosphorus to form calcium phosphate in the bones and teeth. It is essential for the normal functioning of nerves and muscles and plays a role in blood coagulation (as factor IV) and in many enzymatic processes.	Coagulation Factor IV,Factor IV,Blood Coagulation Factor IV,Calcium-40,Calcium 40,Factor IV, Coagulation
D002147	Calmodulin	A heat-stable, low-molecular-weight activator protein found mainly in the brain and heart. The binding of calcium ions to this protein allows this protein to bind to cyclic nucleotide phosphodiesterases and to adenyl cyclase with subsequent activation. Thereby this protein modulates cyclic AMP and cyclic GMP levels.	Calcium-Dependent Activator Protein,Calcium-Dependent Regulator,Bovine Activator Protein,Cyclic AMP-Phosphodiesterase Activator,Phosphodiesterase Activating Factor,Phosphodiesterase Activator Protein,Phosphodiesterase Protein Activator,Regulator, Calcium-Dependent,AMP-Phosphodiesterase Activator, Cyclic,Activating Factor, Phosphodiesterase,Activator Protein, Bovine,Activator Protein, Calcium-Dependent,Activator Protein, Phosphodiesterase,Activator, Cyclic AMP-Phosphodiesterase,Activator, Phosphodiesterase Protein,Calcium Dependent Activator Protein,Calcium Dependent Regulator,Cyclic AMP Phosphodiesterase Activator,Factor, Phosphodiesterase Activating,Protein Activator, Phosphodiesterase,Protein, Bovine Activator,Protein, Calcium-Dependent Activator,Protein, Phosphodiesterase Activator,Regulator, Calcium Dependent
D004591	Electrophoresis, Polyacrylamide Gel	Electrophoresis in which a polyacrylamide gel is used as the diffusion medium.	Polyacrylamide Gel Electrophoresis,SDS-PAGE,Sodium Dodecyl Sulfate-PAGE,Gel Electrophoresis, Polyacrylamide,SDS PAGE,Sodium Dodecyl Sulfate PAGE,Sodium Dodecyl Sulfate-PAGEs
D004789	Enzyme Activation	Conversion of an inactive form of an enzyme to one possessing metabolic activity. It includes 1, activation by ions (activators); 2, activation by cofactors (coenzymes); and 3, conversion of an enzyme precursor (proenzyme or zymogen) to an active enzyme.	Activation, Enzyme,Activations, Enzyme,Enzyme Activations
D036341	Intercellular Signaling Peptides and Proteins	Regulatory proteins and peptides that are signaling molecules involved in the process of PARACRINE COMMUNICATION. They are generally considered factors that are expressed by one cell and are responded to by receptors on another nearby cell. They are distinguished from HORMONES in that their actions are local rather than distal.	Growth Factor,Growth Factors,Paracrine Peptide Factors,Paracrine Protein Factors,Factor, Growth,Factors, Growth,Peptide Factors, Paracrine