Cytosolic protamine kinase is involved in the regulation of protein synthesis and is indirectly associated with numerous cellular processes. Cytosolic protamine kinase is a distinct insulin-stimulated kinase involved in the phosphorylation of eukaryotic Initiation Factor 4E (eIF4E) which is key to initiating translation by mRNA. This protein appears to be inactivated by protein phosphatase 2A family members and may also be inhibited by microcystin, okadeic acid, and ATP. The phosphorylation process is reversible and MBPK1 and MBPK2 (Myelin Basic Protein Kinase 1 and 2) may reactivate cytosolic protamine kinase.http://www.creative-enzymes.com/product/Native-Bovine-Protamine-Kinase-Cytosolic_1639.html