Biochemical and functional characterization of novel NADH kinase in the enteric protozoan parasite Entamoeba histolytica

► NAD(H) kinase gene is essential for growth of the protozoan parasite E. histolytica. ► E. histolytica NAD(H) kinase phosphorylates both NAD+ and NADH. ► E. histolytica and kinetoplastids obtained this gene by lateral gene transfer from proteobacteria. ► NAD(H) kinase is involved in the maintenance of the cellular NADP+/NADPH pool. ► NAD(H) kinase plays an important role in response to oxidative stress.