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. 2012 Dec 31;7(12):e53271. doi: 10.1371/journal.pone.0053271

Figure 3. Use of alternative 5′-triphosphate purine substrates and metal ion dependence of recombinant isozymes.

Figure 3

All values are averages (+/− SD) from triplicate HPLC analyses and referred as reaction rate ratios relative to the reference activity (condition “A”, see Methods). Panel A) Individual isozymes were assayed in the presence of 1 mM ITP or GTP substrates, either replacing 1 mM ATP in the standard assay. Panels B, C, and D) Individual isozymes were assayed at several concentrations of chloride salts of indicated metal ions, each replacing 25 mM MgCl2 in the standard assay. The assays with CoCl2 were also performed in the absence of DTT. mNMNAT1 and WldS data are combined because these were indistinguishable in all conditions tested. Boxed data points refer to the metal ion concentrations selected for discrimination in the present work, i.e., 50 µM MgCl2 (B), 1.5 mM ZnCl2 (C), and 4 mM CoCl2 (D).