The action modes of an extracellular beta-1,3-glucanase isolated from Bacillus clausii NM-1 on beta-1,3-glucooligosaccharides.
The mode of action of an extracellular -1,3-glucanase from Bacillus clausii NM-1 on beta-1,3-3glucooligosaccharides and their alditols was studied. The enzyme could not hydrolyze laminaribiose or laminaritriose. beta-1,3-Glucooligosaccharides higher than laminarihexaose were rapidly hydrolyzed, while laminaritetraose was slowly hydrolyzed. The k(cat)/K(m) ratios for a series of beta-1,3-glucooligosaccharides from laminaritetraose to laminariheptaose showed that the substrate binding site of the enzyme covered a wide range of beta-1,3-glucooligosaccharides having six glucose residues. The action pattern of the enzyme on the alditols corresponding to each laminarioligosaccharide suggested that the catalytic site of the enzyme existed between the third and fourth glucose residue from the non-reducing terminal. The value of k(cat)/K(m) also suggested that the sixth binding position contributed to the catalytic efficiency and stability.
Miyanishi
Nobumitsu
N
Department of Food Science and Technology, Tokyo University of Fisheries, 4-5-7 Konan, Minato-ku, Tokyo 108-8477, Japan.
Matsubara
Yasuhito
Y
Hamada
Naoko
N
Kobayashi
Takeshi
T
Imada
Chiaki
C
Watanabe
Etsuo
E