UDP-glucose pyrophosphorylase (UGPase, UDPGP) E.C=2.7.7.9. is a key enzyme of synthesis of sucrose, cellulose and other saccharides. There are two cytoplasmic isoforms of UGPase-A (which share 94 % identity on amino acid level) and one chloroplastic UGPase-B isoform in Arabidopsis thaliana which share ca. 10-11 % of identity (Kleczkowski et al. 2011). Alternative name: UTP--glucose-1-phosphate uridylyltransferase.