EC - Phosphorylase kinase

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IntEnz Enzyme Nomenclature


Accepted name:
phosphorylase kinase
Other names:
dephosphophosphorylase kinase
glycogen phosphorylase kinase
phosphorylase b kinase
phosphorylase kinase (phosphorylating)
phosphorylase B kinase
Systematic name:
ATP:phosphorylase-b phosphotransferase




Requires Ca2+ and calmodulin for activity. The enzyme phosphorylates a specific serine residue in each of the subunits of the dimeric phosphorylase b. For muscle phosphorylase but not liver phosphorylase, this is accompanied by a further dimerization to form a tetrameric phosphorylase. The enzyme couples muscle contraction with energy production via glycogenolysis—glycolysis by catalysing the Ca2+-dependent phosphorylation and activation of glycogen phosphorylase b [5]. The γ subunit of the tetrameric αβγδ enzyme is the catalytic subunit.

Links to other databases

Enzymes and pathways: NC-IUBMB , BRENDA , ExplorEnz , ENZYME@ExPASy , KEGG , MetaCyc , UniPathway
Protein domains and families: PROSITE:PDOC00100
Structural data: CSA , EC2PDB
Gene Ontology: GO:0004689
CAS Registry Number: 9001-88-1


  1. Krebs, E.G. and Fischer, E.H.
    The phosphorylase b to a converting enzyme of rabbit skeletal muscle.
    Biochim. Biophys. Acta 20: 150-157 (1956). [PMID: 13315361]
  2. Krebs, E.G., Kent, A.B. and Fischer, E.H.
    The muscle phosphorylase b kinase reaction.
    J. Biol. Chem. 231: 73-83 (1958). [PMID: 13538949]
  3. Rall, T.W., Wosilait, W.D. and Sutherland, E.W.
    The interconversion of phosphorylase a and phosphorylase b from dog heart muscle.
    Biochim. Biophys. Acta 20: 69-76 (1956). [PMID: 13315351]
  4. Nikolaropoulos, S. and Sotiroudis, T.G.
    Phosphorylase kinase from chicken gizzard. Partial purification and characterization.
    Eur. J. Biochem. 151: 467-473 (1985). [PMID: 4029141]
  5. Farrar, Y.J. and Carlson, G.M.
    Kinetic characterization of the calmodulin-activated catalytic subunit of phosphorylase kinase.
    Biochemistry 30: 10274-10279 (1991). [PMID: 1931956]
  6. Dasgupta, M. and Blumenthal, D.K.
    Characterization of the regulatory domain of the γ-subunit of phosphorylase kinase. The two noncontiguous calmodulin-binding subdomains are also autoinhibitory.
    J. Biol. Chem. 270: 22283-22289 (1995). [PMID: 7673209]
  7. Lowe, E.D., Noble, M.E., Skamnaki, V.T., Oikonomakos, N.G., Owen, D.J. and Johnson, L.N.
    The crystal structure of a phosphorylase kinase peptide substrate complex: kinase substrate recognition.
    EMBO J. 16: 6646-6658 (1997). [PMID: 9362479]

[EC created 1961 as EC, transferred 2005 to EC]