EC - Procollagen-proline 4-dioxygenase

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IntEnz Enzyme Nomenclature


Accepted name:
procollagen-proline 4-dioxygenase
Other names:
collagen proline hydroxylase
hydroxylase, collagen proline
peptidyl proline hydroxylase
proline hydroxylase
proline protocollagen hydroxylase
proline, 2-oxoglutarate dioxygenase
proline,2-oxoglutarate 4-dioxygenase
prolyl 4-hydroxylase
prolyl hydroxylase
prolyl-glycyl-peptide, 2-oxoglutarate:oxygen oxidoreductase, 4-hydroxylating
prolylprotocollagen dioxygenase
prolylprotocollagen hydroxylase
protocollagen hydroxylase
protocollagen proline 4-hydroxylase
protocollagen proline dioxygenase
protocollagen proline hydroxylase
protocollagen prolyl hydroxylase
procollagen-proline dioxygenase [ambiguous]
P4HA (gene name)
P4HB (gene name)
Systematic name:
procollagen-L-proline,2-oxoglutarate:oxygen oxidoreductase (4-hydroxylating)




Requires Fe2+ and ascorbate. The enzyme, which is located within the lumen of the endoplasmic reticulum, catalyses the 4-hydroxylation of prolines in -X-Pro-Gly- sequences. The 4-hydroxyproline residues are essential for the formation of the collagen triple helix. The enzyme forms a complex with protein disulfide isomerase and acts not only on procollagen but also on more than 15 other proteins that have collagen-like domains.

Links to other databases

Enzymes and pathways: NC-IUBMB , BRENDA , ExplorEnz , ENZYME@ExPASy , KEGG , MetaCyc , UniPathway
Protein domains and families: PROSITE:PDOC00172 , PROSITE:PDOC51471
Structural data: CSA , EC2PDB
Gene Ontology: GO:0004656
CAS Registry Number: 9028-06-2
UniProtKB/Swiss-Prot: (38) [show] [UniProt]


  1. Berg, R.A. and Prockop, D.J.
    Affinity column purification of protocollagen proline hydroxylase from chick embryos and further characterization of the enzyme.
    J. Biol. Chem. 248 : 1175-1182 (1973). [PMID: 4346946]
  2. Hutton, J.J., Jr., Tappel, A.L. and Udenfriend, S.
    Cofactor and substrate requirements of collagen proline hydroxylase.
    Arch. Biochem. Biophys. 118 : 231-240 (1967).
  3. Kivirikko, K.I., Kishida, Y., Sakakibara, S. and Prockop, J.
    Hydroxylation of (X-Pro-Gly)n by protocollagen proline hydroxylase. Effect of chain length, helical conformation and amino acid sequence in the substrate.
    Biochim. Biophys. Acta 271 : 347-356 (1972). [PMID: 5046811]
  4. Kivirikko, K.I. and Prockop, D.J.
    Purification and partial characterization of the enzyme for the hydroxylation of proline in protocollogen.
    Arch. Biochem. Biophys. 118 : 611-618 (1967).
  5. John, D. C., Bulleid, N. J.
    Prolyl 4-hydroxylase: defective assembly of alpha-subunit mutants indicates that assembled alpha-subunits are intramolecularly disulfide bonded.
    Biochemistry 33 : 14018-14025 (1994). [PMID: 7947811]
  6. Lamberg, A., Pihlajaniemi, T., Kivirikko, K. I.
    Site-directed mutagenesis of the alpha subunit of human prolyl 4-hydroxylase. Identification of three histidine residues critical for catalytic activity.
    J. Biol. Chem. 270 : 9926-9931 (1995). [PMID: 7730375]
  7. Myllyharju, J., Kivirikko, K. I.
    Characterization of the iron- and 2-oxoglutarate-binding sites of human prolyl 4-hydroxylase.
    EMBO J. 16 : 1173-1180 (1997). [PMID: 9135134]
  8. Kivirikko, K. I., Myllyharju, J.
    Prolyl 4-hydroxylases and their protein disulfide isomerase subunit.
    Matrix Biol. 16 : 357-368 (1998). [PMID: 9524356]

[EC created 1972, modified 1981, modified 1983, modified 2017]