Expasy logo

ENZYME

ENZYME entry: EC 1.21.99.4

Accepted Name
thyroxine 5'-deiodinase
Alternative Name(s)
diiodothyronine 5'-deiodinase
iodothyronine 5'-deiodinase
iodothyronine outer ring monodeiodinase
L-thyroxine iodohydrolase (reducing)
thyroxine 5-deiodinase
type II iodothyronine deiodinase
type I iodothyronine deiodinase
Reaction catalysed
3,3',5-triiodo-L-thyronine + A + H(+) + iodide <=> AH2 + L-thyroxine
Comment(s)
  • The enzyme activity has only been demonstrated in the direction of 5'-deiodination, which renders the thyroid hormone more active.
  • The enzyme consists of type I and type II enzymes, both containing selenocysteine, but with different kinetics.
  • For the type I enzyme the first reaction is a reductive deiodination converting the -Se-H group of the enzyme into an -Se-I group; the reductant then reconverts this into -Se-H, releasing iodide.
  • Formerly EC 1.97.1.10 and EC 3.8.1.4.
Cross-references
BRENDA 1.21.99.4
EC2PDB 1.21.99.4
ExplorEnz 1.21.99.4
PRIAM enzyme-specific profiles 1.21.99.4
KEGG Ligand Database for Enzyme Nomenclature 1.21.99.4
IUBMB Enzyme Nomenclature 1.21.99.4
IntEnz 1.21.99.4
MEDLINE Find literature relating to 1.21.99.4
MetaCyc 1.21.99.4
Rhea expert-curated reactions 1.21.99.4
UniProtKB/Swiss-Prot
P49894, IOD1_CANLF O42411, IOD1_CHICK Q6V915, IOD1_FELCA
Q804E1, IOD1_FUNHE P49895, IOD1_HUMAN Q61153, IOD1_MOUSE
O42449, IOD1_ORENI Q6QN13, IOD1_PIG A4GT88, IOD1_RABIT
P24389, IOD1_RAT Q95N00, IOD1_SUNMU Q2QEI3, IOD1_XENLA
P49896, IOD2_AQUCT Q5I3B2, IOD2_BOVIN Q9IAX2, IOD2_CHICK
P79747, IOD2_FUNHE Q92813, IOD2_HUMAN Q9Z1Y9, IOD2_MOUSE
Q8UVX8, IOD2_NEOFS L7WGA7, IOD2_PETMA Q6QN12, IOD2_PIG
P70551, IOD2_RAT Q6U6H1, IOD_HALRO

View entry in original ENZYME format
View entry in raw text format (no links)
All UniProtKB/Swiss-Prot entries referenced in this entry, with possibility to download in different formats, align etc.
All ENZYME / UniProtKB/Swiss-Prot entries corresponding to 1.21.99.-
All ENZYME / UniProtKB/Swiss-Prot entries corresponding to 1.21.-.-
All ENZYME / UniProtKB/Swiss-Prot entries corresponding to 1.-.-.-