Altered cofactor binding affects stability and activity of human UDP-galactose 4′-epimerase: Implications for type III galactosemia

► The K161N variant of human GALE is more resistant to denaturation ► K161N has very low detectable NAD+ and greatly reduced enzymatic activity ► The D175N variant is less stable and slightly less active than the wild type ► GALE's activities with UDP-Gal and UDP-GalNAc are not necessarily correlated