text: There are nine sugar nucleotides in humans which act as glycosyl donors and they can be classified depending on the type of the nucleoside forming them:
  *Uridine Diphosphate: UDP-α-D-Glc, UDP-α-D-Gal, UDP-α-D-GalNAc, UDP-α-D-GlcNAc, UDP-α-D-GlcA, UDP-α-D-Xyl
  *Guanosine Diphosphate: GDP-α-D-Man, GDP-β-L-Fuc.
  *Cytidine Monophosphate: CMP-β-D-Neu5Ac; in humans, it is the only nucleotide sugar in the form of nucleotide monophosphate.
  *Cytidine Diphosphate: CDP-D-Ribitol (i.e. CMP-[ribitol phosphate]); though not a sugar, the phosphorylated sugar alcohol ribitol phosphate is incorporated into matriglycan as if it were a monosaccharide.
  In other forms of life many other sugars are used and various donors are utilized for them. All five of the common nucleosides are used as a base for a nucleotide sugar donor somewhere in nature.  As examples, CDP-glucose and TDP-glucose  give rise to various other forms of CDP and TDP-sugar donor nucleotides.