@article{oai:nagano.repo.nii.ac.jp:00000694,
 author = {WAKABAYASHI, Kazumasa and DAICHŌ, Hisayoshi},
 issue = {1},
 journal = {長野大学紀要, ACADEMIC BULLETIN OF NACANO UNIVERSITY},
 month = {Jun},
 note = {application/pdf, The major amylolytic enzyme present in Driselase, a commercial crude cellulase preparation from Irpex lacteus (Polyporus tulipiferae), was purified by fractionation with ammonium sulfate and successive column chromatographies on DEAE-Sephadex and Bio-gel P-100 to homogeneity on polyacrylamide gel electrophoresis and characterized as an α-amylase [E.C.3.2.1.1]. Some properties of the purified α-amylase were investigated. The molecular weight was estimated to be 40,000 by gel filtration on Bio-gel P-100. The activity of the enzyme was significantly inhibited by Ag^+, Cu^<++>, Pb^&;t;++>, or Cd^<++> at the concentration of ion used. The enzyme was completely inhibited by Hg^<++>. The optimum pH and temperature for the activity of the enzyme were pH 6.0 and 50℃. The enzyme was stable over the range pH 5.0-8.0 at 30℃ and was completely inactivated by heating at 60℃ for 30 min. This a-amylase attacked soluble starch, amylose, dextrin, amylopectin, and glycogen, although the relative initial rates of hydrolysis on these glucans were different from one another owing to the structural peculiarities in the glucans, but the enzyme did not act on pullulan. Paper chromatography demonstrated that the α-amylase produced an appreciable amount of G_4 with small amounts of other oligosaccharides without formation of glucose in the initial reaction of hydrolysis when soluble starch was used as substrate. The enzyme also easily hydrolyzed a homologous series of malto-oligosaccharides, having higher molecular sizes than G_4, G_5H, and PNPG_4 to produce various oligosaccharides with maltosyl transfer action without release of glucose under the assay conditions. The highest frequency of cleavage by the enzyme of these malto-oligosaccharides tested in the earlier stage seemed to be at the second α-1, 4-glucosidic linkage from the nonreducing end of a substrate molecule, although the major cleavage point might be shifted from the linkage to others as the molecular size of oligosaccharide increases. Therefore, these findings may be taken to suggest that the hydrolytic action of α-amylase from this fungus on various substrates proceeded in an endo-fashion with incomplete random cleavage.},
 pages = {1--19},
 title = {Purification and Characterization of α-Amylase from Irpex lacteus (Polyporus tulipiferae)},
 volume = {12},
 year = {1990}
}