Purification and Properties of Several Galactanases of Bacillus subtilis var. amylosacchariticus

Two crystalline and one highly purified galactanases were obtained from the culture broth of Bacillus subtilis var. amylosacchariticus (1043) and their chemical and enzymatic properties, especially, their specificities were comparatively studied. Their molecular weights were almost the same, but the isoelectric points were considerably different from each other. The galactanases were sensitive to metal chelators and stabilized by Ca 2+ . The pH optimum of the enzymes were between 6.0 and 7.0. All the galactanases investigated here attacked soybean arabinogalactan without liberation of arabinose, though they were inactive against coffee bean arabinogalactan. In digestion of soybean arabinogalactan, all the galactanases purified here formed galactose, galactobiose and galactotriose whereas the galactanase previously isolated from Bacillus subtilis K-50 produced galactobiose as the main final product.