COMPARATIVE-STUDIES OF BETA-1,3-GLUCANASE-A1 AND BETA-1,3-GLUCANASE-B OF BACILLUS-CIRCULANS-WL-12 - PURIFICATIONS AND ENZYMATIC-PROPERTIES

The beta-1,3-glucan-degrading enzymes of Bacillus circulans WL-12 induced with pachyman, a beta-1,3-glucan, consist of beta-1,3-glucanase A1 (GlcA1), beta-1,3-glucanase B (GlcB) and derivatives of these two glucanases. In order to compare enzymatic properties of the two glucanases, GlcA1 produced by Escherichia coli HB101 carrying a cloned glcA gene, and GLcB produced by both B. circulans WL-12 and E. coli HB101 carrying a cloned glcB gene were purified. Enzymatic properties of purified GlcA1 and GlcB were compared and striking differences were found in the length distributions of the hydrolysis products and the substrate specificities. Purified GlcA1 hydrolyzed pachyman and generated laminarioligosaccharides, from G1 to G5. On the other hand, pachyman hydrolysis by GlcB generated shorter laminarioligosaccharides, G1, G2 and G3. GlcB exhibited higher hydrolyzing activity against mixed-linkage beta-1,3-1,4-glucans than that against beta-1,3-glucan, while GlcA1 did not show any activity on mixed-linkage beta-1,3-1,4-glucans.