Catalyzes the activation of N-acetylneuraminic acid (NeuNAc) to cytidine 5'-monophosphate N-acetylneuraminic acid (CMP-NeuNAc), a substrate required for the addition of sialic acid. Has some activity toward NeuNAc, N-glycolylneuraminic acid (Neu5Gc) or 2-keto-3-deoxy-D-glycero-D-galacto-nononic acid (KDN).
Ubiquitously expressed. Expressed in pancreas, kidney, liver, skeletal muscle, lung, placenta, brain, heart, colon, PBL, small intestine, ovary, testis, prostate, thymus and spleen.
The BC2 (basic cluster 2) motif is necessary and sufficient for the nuclear localization and contains the catalytic active site. The localization in the nucleus is however not required for the enzyme activity.