Galactose mutarotase (aldose 1-epimerase) (gene name GALM) is a human enzyme that reversibly converts α-aldose to the β-anomer.[5] This enzyme catalyzes the first step of the Leloir pathway, which is involved in galactose metabolism.[6] It belongs to family of aldoseepimerases.
The two main amino acids in the enzyme active site are Glu 304, which acts as a Bronsted-Lowry base and abstracts a proton, and His 170, which acts as Bronsted-Lowry Acid to donate a proton to the galactose.[7]