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Proteins/UNIPROT:P49895
Plays a crucial role in the metabolism of thyroid hormones (TH) and has specific roles in TH activation and inactivation by deiodination. Catalyzes the deiodination of L-thyroxine (T4) to 3,5,3'-triiodothyronine (T3), 3,3',5'-triiodothyronine (rT3) to 3,3'-diiodothyronine (3,3'-T2) and 3',5'-diiodothyronine (3',5'-T2) to 3'-monoiodothyronine (3'-T1) via outer-ring deiodination (ORD). Catalyzes the deiodination of T4 to 3,3',5'-triiodothyronine (rT3) via inner-ring deiodination (IRD). Catalyzes the deiodination of T3 to 3,3'-T2, 3,5-diiodothyronine (3,5-T2) to 3- monoiodothyronine (3-T1) and 3,3'-T2 to 3-T1 via IRD (By similarity). Catalyzes the phenolic ring deiodinations of 3,3',5'-triiodothyronamine and 3',5'-diiodothyronamine. Catalyzes the phenolic ring deiodination of 3,3'-diiodothyronamine and tyrosyl ring deiodinations of 3,5,3'-triiodothyronamine and 3,5-diiodothyronamine (By similarity). Catalyzes the deiodination of L-thyroxine sulfate and 3,3',5-triiodo-L-thyronine sulfate via IRD and of 3,3',5'-triiodo-L-thyronine sulfate via ORD (By similarity)..
Function from UniProtKB (P49895), read 2026-09-23. CC BY 4.0.
Curated compounds routed: 1 · substrate of
1 compound
1 compound.
0 reported routes1 assembled route
1 row
64 statements
64 statements · 5 reference databases · Subject: DIO1 · Sources: Bgee, Human-GEM, Reactome, Rhea, WikiPathways
25 reactions
3,3'-diiodo-L-thyronine+iodide+NADP(3-)NADPH(4-)+3,3',5-triiodo-L-thyronine
Catalysed by DIO3 or DIO2 or DIO1
Reaction pageReversibleBalancedEC 1.21.99.4, 1.21.99.3cytosol
Human-GEM MAR06826CC BY 4.0Reference data
6 names
Resolves to: DIO1
Reaction pageReversibleBalancedEC 1.21.99.4, 1.21.99.3endoplasmic reticulum
Human-GEM MAR06827CC BY 4.0Reference data
3,3'-diiodo-L-thyronine+iodide+NADP(3-)NADPH(4-)+MAM02839c
Reaction pageReversibleBalancedEC 1.21.99.4cytosol
Human-GEM MAR06834CC BY 4.0Reference data
3,3'-diiodo-L-thyronine+iodide+NADP(3-)NADPH(4-)+MAM02839r
Reaction pageReversibleBalancedEC 1.21.99.4endoplasmic reticulum
Human-GEM MAR06835CC BY 4.0Reference data
MAM00736c+iodide+NADP(3-)NADPH(4-)+3,3',5-triiodo-L-thyronine
Reaction pageReversibleBalancedEC 1.21.99.4cytosol
Human-GEM MAR06840CC BY 4.0Reference data
MAM00736r+iodide+NADP(3-)NADPH(4-)+3,3',5-triiodo-L-thyronine
Reaction pageReversibleBalancedEC 1.21.99.4endoplasmic reticulum
Human-GEM MAR06841CC BY 4.0Reference data
MAM00736c+NADPH(4-)MAM00828c+iodide+NADP(3-)
Reaction pageReversibleBalancedEC 1.21.99.4cytosol
Human-GEM MAR06848CC BY 4.0Reference data
MAM00736r+NADPH(4-)MAM00828r+iodide+NADP(3-)
Reaction pageReversibleBalancedEC 1.21.99.4endoplasmic reticulum
Human-GEM MAR06849CC BY 4.0Reference data
iodide+NADP(3-)+3,3',5-triiodo-L-thyronineNADPH(4-)+L-thyroxine
Reaction pageReversibleBalancedEC 1.21.99.4cytosol
Human-GEM MAR06854CC BY 4.0Reference data
iodide+NADP(3-)+3,3',5-triiodo-L-thyronineNADPH(4-)+L-thyroxine
Reaction pageReversibleBalancedEC 1.21.99.4endoplasmic reticulum
Human-GEM MAR06855CC BY 4.0Reference data
3,3',5'-triiodo-L-thyronine+iodide+A+hydronL-thyroxine+AH2
Reaction pageRight to leftBalanced
Rhea RHEA:18897CC BY 4.0Reference data
3,3',5-triiodo-L-thyronine+iodide+A+hydronL-thyroxine+AH2
Reaction pageRight to leftBalanced
Rhea RHEA:19745CC BY 4.0Reference data