Reaction: 2 ATP + phosphorylase b = 2 ADP + phosphorylase a
Other name(s): dephosphophosphorylase kinase; glycogen phosphorylase kinase; PHK; phosphorylase b kinase; phosphorylase B kinase; phosphorylase kinase (phosphorylating); STK17
Systematic name: ATP:phosphorylase-b phosphotransferase
Comments: 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: BRENDA, EXPASY, KEGG, Metacyc, PDB, CAS registry number: 9001-88-1
References:
1. Krebs, E.G. and Fischer, E.H. The phosphorylase b to a converting enzyme of rabbit skeletal muscle. Biochim. Biophys. Acta 20 (1956) 150-157. [PMID: 13315361]
2. Krebs, E.G., Kent, A.B. and Fischer, E.H. The muscle phosphorylase b kinase reaction. J. Biol. Chem. 231 (1958) 73-83. [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 (1956) 69-76. [PMID: 13315351]
4. Nikolaropoulos, S. and Sotiroudis, T.G. Phosphorylase kinase from chicken gizzard. Partial purification and characterization. Eur. J. Biochem. 151 (1985) 467-473. [PMID: 4029141]
5. Farrar, Y.J. and Carlson, G.M. Kinetic characterization of the calmodulin-activated catalytic subunit of phosphorylase kinase. Biochemistry 30 (1991) 10274-10279. [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 (1995) 22283-22289. [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 (1997) 6646-6658. [PMID: 9362479]