UDP-glucose 4-epimerase; UDP-galactose 4-epimerase; galactowaldenase (GALE)

Function

• catalyzes 2 distinct but analogous reactions
  • epimerization of UDP-glucose to UDP-galactose
  • epimerization of UDP-N-acetylglucosamine to UDP-N-acetylgalactosamine
• galactose metabolism, 3rd step

Cofactor: NAD

Kinetic parameters:

• KM=69 uM for UDP-galactose (at 37 degrees celsius & pH 8.8)
• Vmax=1.22 mmol/min/mg enzyme with UDP-galactose as substrate

Structure

• homodimer
• belongs to the sugar epimerase family

Pathology

• defects in GALE are the cause of galactosemia 3

Laboratory

• UDP-glucose 4-epimerase in erythrocytes

More general terms

• epimerase

Database

• OMIM: https://mirror.omim.org/entry/230350
• OMIM: https://mirror.omim.org/entry/606953
• UniProt: http://www.uniprot.org/uniprot/Q14376.html