26 Kinases and phosphatases in cell signalling
Phosphorylation
Protein kinases
All protein kinases have regulatory and catalytic elements. These may be contained on separate polypeptide subunits (e.g. cyclic AMP-dependent protein kinase (cA-PK)) (Fig. 3.26.1) or combined in a single polypeptide (e.g. protein kinase C). Protein kinase C is maintained in an inactive form by binding of a regulatory domain with a pseudosubstrate motif to block the active site of the catalytic domain. Binding of diacylglycerol (DAG) and Ca2+