Isolation of extracellular 28- and 42-kilodalton beta-1,3-glucanases and comparison of three beta-1,3-glucanases produced by Bacillus circulans IAM1165.
Bacillus circulans IAM1165 produces three major extracellular beta-1,3-glucanases (molecular masses, 28, 42, and 91 kDa) during the stationary phase of growth. The 28- and 42-kDa enzymes were purified to homogeneity from the culture supernatant in this study. The properties of these two enzymes were examined, together with those of the 91-kDa enzyme previously isolated. The enzymatic properties of the 28- and 42-kDa beta-1,3-glucanases closely resemble each other. The enzymes belong to a category of endo type 1,3-beta-D-glucan glucanohydrolases. The enzymes were active at pH 4.0 to 7.0. The optimum temperature of the reactions was 60 degrees C when laminarin (a soluble beta-1,3-glucan) was used as the substrate at pH 7.0. The enzymes hydrolyzed barley glucan and lichenan (beta-1,3-1,4-glucans) more effectively than laminarin. Of the three enzymes, the 42-kDa enzyme lysed fungal cell walls the most effectively.
Aono
R
R
Department of Bioengineering Faculty of Bioscience and Biotechnology, Tokyo Institute of Technology, Yokohama, Japan.
Hammura
M
M
Yamamoto
M
M
Asano
T
T
D000595:Amino Acid Sequence; D001407:Bacillus / Q000201:enzymology* / Q000254:growth & development; D043326:Glucan 1,3-beta-Glucosidase; D005936:Glucans / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D008969:Molecular Sequence Data; D011134:Polysaccharides / Q000378:metabolism; D016415:Sequence Alignment; D013696:Temperature; D001617:beta-Glucosidase / Q000302:isolation & purification*
D005936:Glucans; D011134:Polysaccharides; C008247:laminaran; D001617:beta-Glucosidase; D043326:Glucan 1,3-beta-Glucosidase; C015968:lichenin