Thymidine kinase 1

Thymidine kinase 1, soluble (gene name TK1), is a human is_associated_with::thymidine kinase.

Two forms of this protein have been identified in animal cells, one in cytosol and one in is_associated_with::mitochondria. Activity of the cytosolic enzyme is high in proliferating cells and peaks during the is_associated_with::S-phase of the is_associated_with::cell cycle; it is very low in resting cells.

Interactions
Thymidine kinase 1 has been shown to interact with is_associated_with::P21.