EC - Thyroxine 5-deiodinase

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IntEnz Enzyme Nomenclature


Accepted name:
thyroxine 5-deiodinase
Other names:
diiodothyronine 5'-deiodinase [ambiguous]
iodothyronine 5-deiodinase
iodothyronine inner ring monodeiodinase
type III iodothyronine deiodinase
Systematic name:
3,3',5'-triiodo-L-thyronine,iodide:acceptor oxidoreductase (iodinating)



The enzyme activity has only been demonstrated in the direction of 5-deiodination. This removal of the 5-iodine, i.e. from the inner ring, largely inactivates the hormone thyroxine. Formerly EC

Links to other databases

Enzymes and pathways: NC-IUBMB , BRENDA , ExplorEnz , ENZYME@ExPASy , KEGG , MetaCyc , UniPathway
Protein domains and families: PROSITE:PDOC00172 , PROSITE:PDOC00925
Structural data: CSA , EC2PDB
Gene Ontology: GO:0033798
UniProtKB/Swiss-Prot: (10) [show] [UniProt]


  1. Chopra, I.J. and Teco, G.N.C.
    Characteristics of inner ring (3 or 5) monodeiodination of 3,5-diiodothyronine in rat liver: evidence suggesting marked similarities of inner and outer ring deiodinases for iodothyronines.
    Endocrinology 110 : 89-97 (1982). [PMID: 7053997]
  2. Körhle, J.
    Iodothyronine deiodinases.
    Methods Enzymol. 347 : 125-167 (2002). [PMID: 11898402]

[EC created 2003 as EC, transferred 2015 to EC]