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1.21.99.4: thyroxine 5'-deiodinase

This is an abbreviated version!
For detailed information about thyroxine 5'-deiodinase, go to the full flat file.

Word Map on EC 1.21.99.4

Reaction

3,3',5-triiodo-L-thyronine
+
Iodide
 +
acceptor
 +
H+
=
L-thyroxine
 +
reduced acceptor

Synonyms

5DI , 5DII , 5DIII , D1 5'-deiodinase, D2 5'-deiodinase, deiodinase, diiodothyronine 5'-deiodinase, Dio, DIO1, DIO2, DIOI , DIOII , DIOIII , EC 1.97.1.10, EC 3.8.1.4, ID-1, ID-2, ID-3, iodothyronine 5'-deiodinase, Iodothyronine 5'-monodeiodinase, iodothyronine 5-deiodinase, iodothyronine deiodinase 2, iodothyronine deiodinase D2, iodothyronine inner ring monodeiodinase, iodothyronine outer ring monodeiodinase, L-thyroxine iodohydrolase (reducing), thyroxine 5-deiodinase, Thyroxine deiodinase, type 1 5'-deiodinase, type 1 deiodinase, Type 1 DI , type 1 iodothyronine deiodinase, type 2 5'-deiodinase, type 2 deiodinase, Type 2 DI , type 2 iodothyronine deiodinase, type 3 deiodinase, Type 3 DI , type I iodothyronine 5'-deiodinase, type I iodothyronine deiodinase, type I-like deiodinase, type II iodothyronine deiodinase, type II-like deiodinase, Type-I 5'deiodinase , Type-II 5'deiodinase , Type-III 5'deiodinase , types 1 iodothyronine selenodeiodinase, types 2 iodothyronine selenodeiodinase, XL-15

ECTree

     1 Oxidoreductases
         1.21 Catalysing the reaction X-H + Y-H = X-Y
             1.21.99 With unknown physiological acceptors
                1.21.99.4 thyroxine 5'-deiodinase

Engineering

Engineering on EC 1.21.99.4 - thyroxine 5'-deiodinase

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PROTEIN VARIANTS
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
A131C
similar Km-values for L-thyroxine and 3,3',5-triiodothyronine as the wild-type enzyme. Mutation improves the interaction with the reducing cofactor dithiothreitol
A131S
similar Km-values for L-thyroxine and 3,3',5-triiodothyronine as the wild-type enzyme. Mutation improves the interaction with the reducing cofactor dithiothreitol
P135S
-
the mutant type 2 iodothyronine deiodinase has many type 1 iodothyronine deiodinase-like properties, a Km (L-thyroxine) in the micromolar range, ping-pong kinetics with dithiothreitol, and sensitivity to 6n-propylthiouracil in vitro. When the P135S mutant is expressed in HEK-293 cells and exposed to 2-200 pM free L-thyroxine, the rate of L-thyroxine to 3,5,3'-triiodo-L-thyronine conversion is identical with type 2 iodothyronine deiodinase and conversion is insensitive to 6n-propylthiouracil. Using glutathione as a cofactor in vitro results in a marked decrease in the Km (L-thyroxine) (as also occurs for type 1 iodothyronine deiodinase), it shows sequential kinetics with L-thyroxine and is sensitive to 6n-propylthiouracil but is resistant when HEK-293 cytosol is used as a cofactor
SeC133A
inactive mutant enzyme
SeC133C
SeC133C/A131C
mutant enzyme with more than 1000fold increase in Km-value for L-thyroxine
N203Q
decrease in Km-value for 3,3',5-triiodo-L-thyronine sulfate
N94Q
decrease in Km-value for 3,3',5-triiodo-L-thyronine sulfate
N94Q/N203Q
increase in Km-value for 3,3',5-triiodo-L-thyronine sulfate
S101A
Km-value for 3,3',5-triiodo-L-thyronine sulfate is nearly identical
S101A/S176A
increase in Km-value for 3,3',5-triiodo-L-thyronine sulfate
Y209F/Y217F
increase in Km-value for 3,3',5-triiodo-L-thyronine sulfate
additional information