Enables thymidylate kinase activity. Acts upstream of or within cellular response to growth factor stimulus and dTDP biosynthetic process. Predicted to be located in mitochondrial intermembrane space and mitochondrial matrix. Predicted to be active in mitochondrion and nucleus. Is expressed in several structures, including alimentary system; forebrain; genitourinary system; midbrain; and respiratory system. Orthologous to human DTYMK (deoxythymidylate kinase). [provided by Alliance of Genome Resources, Apr 2022]