Open AccessSubstrate specificity of the cyclic AMP-dependent protein kinase.
Author(s) -
Bruce E. Kemp,
David B. Bylund,
Tung-Shiuh Huang,
Edwin G. Krebs
Publication year - 1975
Publication title -
proceedings of the national academy of sciences of the united states of america
Language(s) - English
Resource type - Journals
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.72.9.3448
Subject(s) - casein kinase 2 , phosphotransferase , phosphorylation , protein kinase a , casein kinase 2, alpha 1 , biochemistry , serine , protein subunit , casein kinase 1 , biology , protein phosphorylation , cgmp dependent protein kinase , chemistry , cyclin dependent kinase 2 , gene
The protein substrate specificity of the catalytic subunit of rabbit skeletal muscle cyclic AMP-dependent protein kinase (EC 2.7.1.37; ATP:protein phosphotransferase) has been studied using genetic variants of beta casein. It was found that beta casein-B was phosphorylated at a much greater rate than beta caseins A1, A2, A3, or C. The enhanced phosphorylation of beta casein-B, as compared with the most common variant A2, was attributed to an arginine substitution for a serine at position 122, which caused a nearby residue, serine 124, to become a phosphorylation site for the protein kinase. These results further support the concept that the local primary structure is important in specificity and that arginine may be a specific determinant common to all the local phosphorylation site sequences recognized by the cyclic AMP-dependent protein kinase.