Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. In enzymology, an UDP-glucosamine 4-epimerase (EC 5.1.3.16) is an enzyme that catalyzes the chemical reaction. UDP-glucosamine = UDP-galactosamine. Hence, this enzyme has one substrate, UDP-glucosamine, and one product, UDP-galactosamine. This enzyme belongs to the family of isomerases, specifically those racemases and epimerases acting on carbohydrates and derivatives. The systematic name of this enzyme class is UDP-glucosamine 4-epimerase.