Abstract
The hydrolyzate of partially N-acetylated chitosan by Bacillus sp. No. 7-M chitosanase was separated by gel filtration on Bio-Gel P-2. Sugar compositions and sequences of the oligosaccharides were identified by exo-splitting with β-GlcNase, fast atom bombardment mass spectroscopy, and proton NMR spectroscopy. In addition to chitooligosaccharides, (GlcN)2, (GlcN)3, and (GlcN)4, hetero-chitooligosaccharides such as (GlcN)2·GlcNAc·(GlcN)2, GlcN·GlcNAc·(GlcN)3, (GlcN)2, ·GlcNAc·(GlcN)3, and GlcN·GlcNAc·(GlcN)4 were detected. These results indicate that Bacillus sp. No. 7-M chitosanase is absolutely specific toward the GlcN·GlcN bonds in partially N-acetylated chitosan and at least three GlcN residues were necessary to the hydrolysis of chitosan by chitosanase.
