4-diphosphocytidyl-2C-methyl-D-erythritol kinase is a member of the family of GHMP kinases that were previously designated as conserved hypothetical protein YchB or as isopentenyl monophosphate kinase. In <taxon tax_id="4081">Solanum lycopersicum</taxon> (Tomato) (Lycopersicon esculentum) and <taxon tax_id="562">Escherichia coli</taxon> the protein has been indentified as 4-diphosphocytidyl-2C-methyl-D-erythritol kinase, an enzyme of the deoxyxylulose phosphate pathway of terpenoid biosynthesis.