Nucleoside diphosphate (NDP) kinases (EC 2.7.4.6), such as NME6, are ubiquitous enzymes that catalyze transfer of gamma-phosphates, via a phosphohistidine intermediate, between nucleoside and dioxynucleoside tri- and diphosphates (Mehus et al., 1999 [PubMed 10453732]).[supplied by OMIM, Jul 2010].