Thymidine kinase 1, soluble (gene name TK1), is a human
thymidine kinase
Thymidine kinase is an enzyme, a phosphotransferase (a kinase): 2'-deoxythymidine kinase, ATP-thymidine 5'-phosphotransferase, EC 2.7.1.21. It can be found in most living cells. It is present in two forms in mammalian cells, TK1 and TK2. Cert ...
.
Two forms of this protein have been identified in animal cells, one in cytosol and one in
mitochondria
A mitochondrion (; ) is an organelle found in the Cell (biology), cells of most Eukaryotes, such as animals, plants and Fungus, fungi. Mitochondria have a double lipid bilayer, membrane structure and use aerobic respiration to generate adenosi ...
. Activity of the cytosolic enzyme is high in proliferating cells and peaks during the
S-phase
S phase (Synthesis Phase) is the phase of the cell cycle in which DNA is replicated, occurring between G1 phase and G2 phase. Since accurate duplication of the genome is critical to successful cell division, the processes that occur during ...
of the
cell cycle
The cell cycle, or cell-division cycle, is the series of events that take place in a cell that cause it to divide into two daughter cells. These events include the duplication of its DNA (DNA replication) and some of its organelles, and subs ...
; it is very low in resting cells.
Interactions
Thymidine kinase 1 has been shown to
interact
Advocates for Informed Choice, dba interACT or interACT Advocates for Intersex Youth, is a 501(c)(3) nonprofit organization using innovative strategies to advocate for the legal and human rights of children with intersex traits. The organizati ...
with
P21
p21Cip1 (alternatively p21Waf1), also known as cyclin-dependent kinase inhibitor 1 or CDK-interacting protein 1, is a cyclin-dependent kinase inhibitor (CKI) that is capable of inhibiting all cyclin/CDK complexes, though is primarily associated ...
.
Interactive pathway map
Thymidine Kinase 1 in Cancer
Elevations in serum TK-1 have been found to correlate with the return of breast and other forms of cancer
TK-1 can be used to detect cancer earlier, determine what stage it is in, and detect recurrence. Thymidine Kinase 1 can be measured based on its enzyme activity
or using immunoassay.
References
Further reading
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