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Mimicking phosphorylation of Ser‐74 on human deoxycytidine kinase selectively increases catalytic activity for dC and dC analogues
Author(s) -
McSorley Theresa,
Ort Stephan,
Hazra Saugata,
Lavie Ar,
Konrad Manfred
Publication year - 2008
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/j.febslet.2008.01.048
Subject(s) - deoxycytidine kinase , phosphorylation , transfection , nucleoside , kinase , chemistry , biochemistry , enzyme , microbiology and biotechnology , biology , deoxycytidine , gene , cancer , genetics , gemcitabine
Intracellular phosphorylation of dCK on Ser‐74 results in increased nucleoside kinase activity. We mimicked this phosphorylation by a Ser‐74‐Glu mutation in bacterially produced dCK and investigated kinetic parameters using various nucleoside substrates. The S74E mutation increases the k cat values 11‐fold for dC, and 3‐fold for the anti‐cancer analogues dFdC and AraC. In contrast, the rate is decreased for the purine substrates. In HEK293 cells, we found that by comparing transiently transfected dCK(S74E)‐GFP and wild‐type dCK‐GFP, mimicking the phosphorylation of Ser‐74 has no effect on cellular localisation. We note that phosphorylation may represent a mechanism to enhance the catalytic activity of the relatively slow dCK enzyme.