- Uridine 5'-polyphosphates (p4U and p5U) and uridine(5')polyphospho(5')nucleosides (Up(n)Ns) can be synthesized by UTP:glucose-1-phosphate uridylyltransferase from Saccharomyces cerevisiae. Guranowski, A., de Diego, A., Sillero, A., Günther Sillero, M.A. FEBS Lett. (2004)