• The addition of a phosphate group to one or more sites on the protein, which alters the activity of the protein
    • Usually exchanges hydroxyl R group with phosphate
    • Switches proteins on → increases potential energy and ability for chemical work
  • Protein phosphorylation involved with regulation of transcription, enzymes and TRKs
  • The transfer of the phosphate group is catalyzed by the kinase enzyme
    • Cells contain many different kinases that phosphorylate different targets
  • The reverse: after a protein has been “activated”, the enzyme phosphatases switches them back into non-phosphorylated state by catalyzing removal of phosphates

               Turns of kinase cascades