The single deoxynucleoside kinase in Drosophila melanogaster, Dm-dNK, is multifunctional and differs from the mammalian deoxynucleoside kinases.

Abstract

In mammalian cells, four enzymes are responsible for the salvage of deoxyribonucleosides. The thymidine kinases TK1 and TK2, the deoxycytidine kinase dCK and the deoxyguanosine kinase, dGK. TK1 is expressed only in dividing cells1 and phosphorylates thymidine and deoxyuridine. The other three kinases are constitutively expressed. TK2 is located in the mitochondria and is also an efficient deoxycytidine and deoxyuridine kinase.2 dCK phosphorylates deoxycytidine, deoxyadenosine and deoxyguanosine,3 and the newly isolated mithochondrial dGK can also phosphorylate deoxyadenosine.4 The genes of the four human enzymes have been cloned,5–8 and homology and enzymatic studies indicate that human TK1 together with mammalian TK1 from mouse and chicken are closely related to pox-viral TK’s and TK from E. coli,9 whereas human dCK, dGK and TK2 shares many properties with Herpetic TK’s.8 KeywordsThymidine KinaseNucleoside AnalogNative SizeThymidine Kinase GeneThymidine Kinase ActivityThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.