A) Relative substrate activity of DR_0079 towards a variety of nucleoside di- and triphosphate substrates. B) Nudix hydrolase activity of DR_0079 as a function of metal cation. The divalent cation requirements (metal profile) were determined towards CDP in the presence of 5 mM Mg2+ or 0.5 mM other divalent cation (Mn2+, Co2+, Ni2+, Zn2+, Ca2+, or Cu2+).