Characterization of Oligomeric and Kinetic Properties of Tomato Thymidine Kinase 1

Zeeshan Mutahir, Nicolai Balle Larsen, Karl-Magnus Andersson, Louise Slot Christiansen, Ricardo Rico, Sofia Mebrahtu Wisen, Anders Ranegaard Clausen, Birgitte Munch-Petersen, Jure Piskur

    Research output: Contribution to journalJournal articleResearchpeer-review

    Abstract

    The gene encoding thymidine kinase 1 from tomato (toTK1) has in combination with azidothymidine (AZT) recently been proposed as a powerful suicide gene for anticancer gene therapy. The toTK1/AZT combination has been demonstrated to have several advantages for the treatment of glioblastomas because AZT can easily penetrate the blood–brain barrier and toTK1 can efficiently phosphorylate AZT and also AZT-monophosphate. In a pursuit to further understand the properties of toTK1, we examined the oligomerization properties of recombinant toTK1 and its effect on enzyme kinetics. Previously, it has been shown that human TK1 is a dimer in the absence of ATP and a tetramer if preincubated with ATP. However, we show here that ATP reincubation did not result in a structural shift from dimer to tetramer in toTK1. For human TK1 pretreated with ATP, the Km value decreased 20-fold, but toTK1’s Km value did not show a dependence on the presence or absence of ATP. Furthermore, toTK1 was always found in a highly active form.
    Original languageEnglish
    JournalNucleosides, Nucleotides and Nucleic Acids
    Volume30
    Issue number12
    Pages (from-to)1223-1226
    Number of pages4
    ISSN1525-7770
    DOIs
    Publication statusPublished - 2011

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