XK and infection: To determine whether SARS-CoV-2 also dysregulates the NAD system upon infection, we assembled and analyzed a set of 71 genes that encode the enzymes responsible for conversion of tryptophan, NA, NAM, and NR to NAD+, plus the enzymes responsible for NAD(H) phosphorylation, NADP(H) dephosphorylation, NAD+-dependent deacylation, MARylation, PARylation, cADP-ribose formation, nicotinamide methylation/oxidation, and other related functions in transport, binding, redox, and regulation (supporting material 1).