This enzyme, isolated from the bacterium Bacillus subtilis, hydrolyses the beta(1->4) bonds found in type I plant arabinogalactans, which are a component of the primary cell walls of dicots. The predominant product is a tetrasaccharide. cf. EC 188.8.131.52, galactan endo-beta-1,3-galactanase.
initially, rather long oligosaccharides are detected as hydrolysis products of potato galactan. Then, as the reaction proceeds, mainly galactotetraose is produced. After 24 h reaction, D-galactose, beta-1,4-D-galactobiose, beta-1,4-D-galactotriose and beta-1,4-D-galactotetraose are detected as the major products from potato galactan. The enzyme hydrolyzes galactans more efficiently than pectic galactans
activity with galactans from different sources, overview, the enzyme is highly active and specific for beta-galactans hydrolyzing beta-1,4-galactosidic linkages, substrate specificity, the enzyme acts on beta-1,4-linked galactan, producing a range of galacto-oligosaccharides, and on beta-1,4- and beta-1,3/6-linked arabinogalactans, the enzyme liberates galactose from a lignin–carbohydrate complex isolated from softwood kraft pulp, no activity towards beta-1,3-liked galactan, overview
purified enzyme free or in complex with products galactobiose and galactotriose, hanging drop vapour diffusion method, 0.002-0.004 ml of protein solution, containing 20-40 mg/ml protein, are mixed with 0.002 ml reservoir solution containing 21-26% w/v PEG 1500, X-ray diffraction structure determination and analysis at 2.6 A resolution, molecular replacement modelling
wild-type and mutant E263A in complex with methyl-beta(1-4)-galactotetraoside, grown at room temperature in hanging drops with a resolution range of 30-2.3 A. Crystals of wild-type and mutant E263A both belong to the monoclinic space group P21, containing two molecules in the asymmetric unit
enzyme retains at least 80% of its activity between pH 4.4 and pH 7 at 40°C after 24 h, but loses 50% of its activity below pH 3.2 and above pH 7.5; purified enzyme, 24 h, 40°C, 80% remaining activity at pH 4.4 and pH 7.0, less than 50% remaining activity below pH 3.2 and above pH 7.5