Oxidoreductases;
Acting on paired donors, with incorporation or reduction of molecular oxygen;
Miscellaneous
BRITE hierarchy

[histone H3]-N6,N6-dimethyl-L-lysine4:acceptor oxidoreductase (demethylating)

a [histone H3]-N6,N6-dimethyl-L-lysine4 + 2 acceptor + 2 H2O = a [histone H3]-L-lysine4 + 2 formaldehyde + 2 reduced acceptor (overall reaction) [RN:R12462];
(1a) a [histone H3]-N6,N6-dimethyl-L-lysine4 + acceptor + H2O = a [histone H3]-N6-methyl-L-lysine4 + formaldehyde + reduced acceptor [RN:R12463];
(1b) a [histone H3]-N6-methyl-L-lysine4 + acceptor + H2O = a [histone H3]-L-lysine4 + formaldehyde + reduced acceptor [RN:R12464]

R12462 R12463 R12464
Reaction

[histone H3]-N6,N6-dimethyl-L-lysine4;
acceptor [CPD:C00028];
H2O [CPD:C00001];
[histone H3]-N6-methyl-L-lysine4

The enzyme specifically removes methyl groups from mono- and dimethylated lysine4 of histone 3. During the reaction the substrate is oxidized by the FAD cofactor of the enzyme to generate the corresponding imine, which is subsequently hydrolysed in the form of formaldehyde.The enzyme is similar to flavin amine oxidases, and differs from all other known histone lysine demethylases, which are iron(II)- and 2-oxoglutarate-dependent dioxygenases. The physiological electron acceptor is not known with certainty. In vitro the enzyme can use oxygen, which is reduced to hydrogen peroxide, but generation of hydrogen peroxide in the chromatin environment is unlikely as it will result in oxidative damage of DNA.

EC 1.14.99.66 created 2019

1  [PMID:15811342]

2  [PMID:19624733]