A novel enzyme, maltose 1-epimerase fromLactobacillus brevisIFO 3345

Abstract
A novel enzyme, maltose 1-epimerase (MER), that catalyzes the interconversion of α and β anomers of maltose was found in a cell-free extract of Lactobacillus brevis IFO 3345, and MER was purified to homogeneity from the crude extract. The Mr of the enzyme was estimated to be 43,000 and 45,000 by HPLC gel filtration and SDS-PAGE, respectively. It showed optimum activity at pH 6.5–7.0. This novel enzyme catalyzed the conversion of β-maltose more effectively than disaccharides such as α-lactose and β-cellobiose, whereas the relative velocities for β- and α-d-glucose were about one forth of that for β-maltose