UGPase
Sugar are the ultimate source of energy and carbon skeletons for all biomolecules, and they provide the material out of which a plant builds its cell walls, fibers, and wood. UGPase plays key role in carbohydrate metabolism by catalyzing reversible reaction of Glucose-1-phosphate and UTP into Uridine diphosphate glucose (UDPG) and pyrophosphate (PPi). Sucrose biosynthesis occuring in young and mature leaves uses UDPG provided by UGPase for Sucrose phosphate synthetase (SPS). While in mature apical leaves UGPase might help in breakdown of sucrose by using UDPG produced by Sucrose synthase. In endosperm, use of UDPG by UGPase is coupled to the activity of cytosolic ADP-Glc pyrophosphorylase. Both UDPG and ADP-Glc pyrophosphorylase poduction is equal in concentration in tissue. Therefore forming close interaction between Sucrose metabolism and starch synthesis as ADP-Glucose is precursor of starch synthesis.
Predicted Structure of Rice UGPase
Predicted phylogeny of UGPase sequence
