EC - Glycogen phosphorylase

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IntEnz Enzyme Nomenclature


Accepted name:
glycogen phosphorylase
Other names:
1,4-α-glucan phosphorylase
α-glucan phosphorylase
amylopectin phosphorylase
glucan phosphorylase
glucosan phosphorylase
granulose phosphorylase
maltodextrin phosphorylase
muscle phosphorylase
muscle phosphorylase a and b
potato phosphorylase
starch phosphorylase
1,4-α-D-glucan:phosphate α-D-glucosyltransferase
phosphorylase [ambiguous]
Systematic name:
(1→4)-α-D-glucan:phosphate α-D-glucosyltransferase



This entry covers several enzymes from different sources that act in vivo on different forms of (1→4)-α-D-glucans. Some of these enzymes catalyse the first step in the degradation of large branched glycan polymers - the phosphorolytic cleavage of α-1,4-glucosidic bonds from the non-reducing ends of linear poly(1→4)-α-D-glucosyl chains within the polymers. The enzyme stops when it reaches the fourth residue away from an α-1,6 branching point, leaving a highly branched core known as a limit dextrin. The accepted name of the enzyme should be modified for each specific instance by substituting "glycogen" with the name of the natural substrate, e.g. maltodextrin phosphorylase, starch phosphorylase, etc.

Links to other databases

Enzymes and pathways: NC-IUBMB , BRENDA , DIAGRAM , ExplorEnz , ENZYME@ExPASy , KEGG , MetaCyc , UniPathway
Protein domains and families: PROSITE:PDOC00095
Structural data: CSA , EC2PDB
Gene Ontology: GO:0004645 , GO:0102499 , GO:0102250
CAS Registry Number: 9035-74-9
UniProtKB/Swiss-Prot: (50) [show] [UniProt]


  1. Baum, H. and Gilbert, G.A.
    A simple method for the preparation of crystalline potato phosphorylase and Q-enzyme.
    Nature 171 : 983-984 (1953). [PMID: 13063502]
  2. Chen, G.S. and Segel, I.H.
    Purification and properties of glycogen phosphorylase from Escherichia coli.
    Arch. Biochem. Biophys. 127 : 175-186 (1968). [PMID: 4878695]
  3. Cowgill, R.W.
    Lobster muscle phosphorylase: purfication and properties.
    J. Biol. Chem. 234 : 3146-3153 (1959). [PMID: 13812491]
  4. Fischer, E.H., Pocker, A. and Saari, J.C.
    The structure, function and control of glycogen phosphorylase.
    In: Campbell, P.N. and Greville, G.D. (Eds.) Essays in Biochemistry, vol. 6 , Academic Press , London and New York , 1970 , 23-68
  5. Green, A.A. and Cori, G.T.
    Crystalline muscle phosphorylase. I. Preparation, properties, and molecular weight.
    J. Biol. Chem. 151 : 21-29 (1943).
  6. Hanes, C.S.
    The breakdown and synthesis of starch by an enzyme from pea seeds.
    Proc. R. Soc. Lond. B Biol. Sci. 128 : 421-450 (1940).

[EC created 1961, modified 2013]