Galactose, one of the eight essential monosaccharide?s (Section 25.7), is biosynthesized from UDP-glucose by galactose 4-epimerase, where

Question:

Galactose, one of the eight essential monosaccharide?s (Section 25.7), is biosynthesized from UDP-glucose by galactose 4-epimerase, where UDP = uridylyl diphosphate (a ribonucleotide diphosphate; Section 28.1). The enzyme requires NAD⁺ for activity (Section 1 7.7), hut it is not a stoichiometric reactant, and NADII is not a final reaction product. Propose a mechanism.