Topic summary
UDP-galactose
Extracted from the Wikipedia article Uridine diphosphate galactose.
Sugar metabolism
To further explain, UDP-galactose is derived from a galactose molecule which is an epimer of glucose, and via the Leloir pathway, it is used be used as a precursor for the metabolism of glucose into pyruvate. When lactose is hydrolyzed, D-Galactose enters the liver via the bloodstream. There, galactokinase phosphorylates it to galactose-1-phosphate using ATP. This compound then engages in a "ping-pong" reaction with UDP-glucose, catalyzed by uridylyltransferase, yielding glucose-1-phosphate and UDP-galactose. This glucose-1-phosphate feeds into glycolysis, while UDP-galactose undergoes epimerization to regenerate UDP-glucose.