In enzymology, a galactose dehydrogenase (EC 220.127.116.11) is an enzyme that catalyzes the chemical reaction: D-galactose + NAD+ rightleftharpoons D-galactono-1,4-lactone + NADH + H+. Thus, the two substrates of this enzyme are D-galactose and NAD+, whereas its 3 products are D-galactono-1,4-lactone, NADH, and H+. This enzyme belongs to the family of oxidoreductases, specifically those acting on the CH-OH group of donor with NAD+ or NADP+ as acceptor. This enzyme participates in galactose metabolism. An aldose 1-epimerase (EC 18.104.22.168) is an enzyme that catalyzes the chemical reaction:alpha-D-glucose↔ beta-D-glucose. Hence, this enzyme has one substrate, alpha-D-glucose, and one product, beta-D-glucose. This enzyme belongs to the family of isomerases, specifically those racemases and epimerases acting on carbohydrates and derivatives. This enzyme participates in glycolysis and gluconeogenesis.