|PROSITE documentation PDOC00006|
Casein kinase II (CK-2) is a protein serine/threonine kinase whose activity is independent of cyclic nucleotides and calcium. CK-2 phosphorylates many different proteins. The substrate specificity  of this enzyme can be summarized as follows:
(1) Under comparable conditions Ser is favored over Thr. (2) An acidic residue (either Asp or Glu) must be present three residues from the C-terminal of the phosphate acceptor site. (3) Additional acidic residues in positions +1, +2, +4, and +5 increase the phosphorylation rate. Most physiological substrates have at least one acidic residue in these positions. (4) Asp is preferred to Glu as the provider of acidic determinants. (5) A basic residue at the N-terminal of the acceptor site decreases the phosphorylation rate, while an acidic one will increase it.Note:
This pattern is found in most of the known physiological substrates.Last update:
May 1991 / Text revised.
PROSITE method (with tools and information) covered by this documentation:
|Title||Casein kinase 2: an 'eminence grise' in cellular regulation?|
|Source||Biochim. Biophys. Acta 1054:267-284(1990).|