Title: Studies on amylases from Bacillus effective for production of maltose. II. Purifications and enzymatic properties of .BETA.-amylase and pullulanase from Bacillus cereus var. mycoides.
Abstract: A β-amylase and a pullulanase produced by Bacillus cereus var. mycoides were purified by means of ammonium sulfate fractionation, adsorption on starch and celite and Sephadex G-100 column chromatography. The purified enzymes were homogeneous in disc electrophoresis. The β-amylase released only maltose from amylose, amylopectin, starch and glycogen, and the released maltose was in β-form. The pullulanase released maltose, maltotriose and maltotetraose from β-limit dextrin and maltotriose from pullulan, but not amylose-like substance from amylopectin. The optimtmi pHs of β-amylase and pullulanase were about 7 and 6_??_6.5, respectively. The optimum temperatures of the enzymes were about 50°C. The enzymes were inhibited by the sulfhydryl reagents such as mercuric chloride and p-chloromercuribenzoate, and the inhibitions with p-chloromercuribenzoate were restored by the addition of cysteine. The molecular weights of β-amylase and pullulanase were estimated to be 35, 000±5, 000 and 110, 000±20, 000, respectively.