Galactose Mutarotase (GALM)

Galactose mutarotase catalyzes the conversion of beta-D-galactose to alpha-D-galactose during normal galactose metabolism . addition of GALM to sugar solutions of galactose or glucose resulted in an increase in the sugar mutarotation rate, with a higher rate observed for galactose. Timson and Reece (2003) individually mutated 3 GALM residues implicated in catalysis by the crystal structure of L. lactis Galm and found that the mutant GALM proteins had reduced mutarotase activity.GALM folds into 2 alpha helices and 29 beta strands connected by 25 classical reverse turns. Two cis-peptide bonds are present, and the side chains of glu307 and his176 are in locations appropriate to act as catalytic base and acid, respectively. No significant structural changes were observed upon galactose binding to GALM.