Diversity of Regulatory Phosphorylation of the Na+/K+-ATPase from Mammalian Kidneys and XenopusOocytes by Protein Kinases: Characterization of the Phosphorylation Site for Protein Kinase C

1997 ◽  
Vol 7 (1) ◽  
pp. 1-18 ◽  
Author(s):  
Larisa A. Vasilets
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Protein Kinases ◽  
Phosphorylation Site ◽  
Kinase C ◽  
Regulatory Phosphorylation

scholarly journals A potent and highly selective peptide substrate for protein kinase C assay

1997 ◽  
Vol 322 (2) ◽  
pp. 455-460 ◽  
Author(s):  
Reet TOOMIK ◽  
Pia EK
Keyword(s):  
Amino Acids ◽  
Protein Kinase C ◽  
Protein Kinase ◽  
Protein Kinases ◽  
Phosphorylation Site ◽  
Phosphorylation Sites ◽  
Cell Extracts ◽  
Kinase C ◽  
Km Value ◽  
Peptide Phosphorylation

Protein kinases exhibit substrate specificities that are often primarily determined by the amino acids around the phosphorylation sites. Peptides corresponding to protein kinase C phosphorylation sites in several different proteins were synthesized on SPOTs membrane which has recently been found to be applicable for studies of protein kinase specificity. After phosphorylation with protein kinase C, we chose the best phosphorylated peptides for the investigation of the importance of amino acids immediately adjacent to the phosphorylation site. The selectivity of the best protein kinase C substrates from this study was analysed with protein kinases A, CK1 and CK2. According to these tests, the most favourable characteristics of SPOTs-membrane-associated peptides were demonstrated by peptide KRAKRKTAKKR. Kinetic analysis of peptide phosphorylation with protein kinase C revealed an apparent Km of 0.49±0.13 μM and Vmax of 10.0±0.5 nmol/min per mg with soluble peptide KRAKRKTAKKR. In addition, we assayed several other soluble peptides commonly used as protein kinase C substrates. Peptide KRAKRKTAKKR showed the lowest Km and the highest Vmax/Km value in comparison with peptides FKKSFKL, pEKRPSQRSKYL and KRAKRKTTKKR. Furthermore, of the peptides tested, KRAKRKTAKKR was the most selective substrate for protein kinase C. The favourable kinetic parameters combined with the selectivity should make the KRAKRKTAKKR peptide useful as a substrate for protein kinase C in the assays of both purified enzyme and in crude cell extracts.

scholarly journals Amino acid sequence and characterization of a protein inhibitor of protein kinase C.

1990 ◽  
Vol 265 (8) ◽  
pp. 4583-4591 ◽  
Author(s):  
J D Pearson ◽  
D B DeWald ◽  
W R Mathews ◽  
N M Mozier ◽  
H A Zürcher-Neely ◽  
...  
Keyword(s):  
Protein Kinase C ◽  
Amino Acid ◽  
Protein Kinase ◽  
Amino Acid Sequence ◽  
Protein Inhibitor ◽  
Kinase C
Sign in / Sign up

Export Citation Format

Share Document