The enzymes hexokinase in muscle and hexokinase in liver convert glucose to glucose 6-phosphate. Phosphoglucomutase catalyses the conversion of glucose 6-phosphate to glucose 1-phosphate. Uridine diphosphate glucose (UDPG) is synthesised from glucose 1-phosphate and UTP by UDP-glucose phosphorylase. Pyrophosphate (PPi) produced in this reaction is hydrolysed to inorganic phosphate, which will ensure the optimal synthesis of UDPG.