Thymidine kinase

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Thymidine kinase
Thymidine kinase
Thymidine kinase tetramer, Leishmania major according to PDB  4UXJ

Existing structural data : 1w4r , 1xbt , 2orv

Properties of human protein
Mass / length primary structure 234 amino acids
Identifier
Gene name TK1
External IDs
Enzyme classification
EC, category 2.7.1.21 ,  kinase
Response type Phosphorylation
Substrate ATP + thymidine
Products ADP + thymidine-5'-phosphate
Occurrence
Homology family Thymidine kinase
Parent taxon Creature

The thymidine kinase (TK) is that enzyme in all living beings, the deoxythymidine to Desoxythymidinphosphat converts (dTMP). It is therefore essential in building DNA . In particular, proliferating cells in the interphase produce this enzyme. The mitochondria in eukaryote cells have their own variant that is not cell cycle regulated .

Catalyzed reaction

2'-deoxythymidine.svg+ ATP → 2'-deoxythymidine monophosphate.svg+ ADP

Deoxythymidine reacts with ATP to form dTMP and ADP. The nucleoside thus became the nucleotide which, in order to be incorporated into DNA by a DNA polymerase, has to be converted into thymidine triphosphate by a thymidylate kinase and furthermore into thymidine triphosphate by a nucleoside diphosphate kinase.

Despite their name, thymidine kinases are relatively non-specific in many organisms . Cytosine and uridine, as well as their deoxy derivatives, and also guanosine analogues such as acyclovir can be phosphorylated.

Importance in medicine

Since thymidine kinase (TK) is an enzyme that is involved in the incorporation of the nucleoside thymidine into DNA, its concentration is a measure of the cell division activity. In the case of malignant diseases of the hematopoietic and lymphatic system in particular, its value is above the normal value of <5 U / l and is therefore a tumor marker that provides information on progress and progress in acute and chronic leukemia , non-Hodgkin's lymphoma and multiple myeloma can give the prognosis of the disease. The TC is determined in the laboratory using the radioimmunoassay (RIA).

Individual evidence

  1. ↑ Kit S: Thymidine kinase . In: Microbiol. Sci. . 2, No. 12, December 1985, pp. 369-75. PMID 3939993 .
  2. ↑ Wintersberger E: Regulation and biological function of thymidine kinase . In: Biochem. Soc. Trans. . 25, No. 1, February 1997, pp. 303-8. PMID 9056888 .
  3. ↑ EC  2.7.1.21
  4. ^ M. Hallek, B. Emmerich, MR Nowrousian: Individual Risk Assessment for Patients with Haematological Malignancies, Georg Thieme Verlag 1999

Web links

Wikibooks: Biochemistry and Pathobiochemistry: Pyrimidine Metabolism  - Learning and Teaching Materials