Properties and Action Pattern of a Chitosanase from Bacillus sp. PI-7S.

Chitosan is a 7V-deacetylated form of chitin. Chitosanase hydrolyzes chitosan into GlcN-oligomers, and many chitosanases have been isolated from microorganisms. Some of these enzymes hydrolyze not only chitosan but also carboxymethyl cellulose (CMC).1-3) In a few studies,4'5) it has been reported that the 7V-acetylglcosamine residues in chitosan are important in the recognition of the substrate by the enzyme, as chitosanases need them to show the highest activity. We found a new type of chitosanase from Bacillus sp. PI-7S,6) which shows the highest activity for chitosan deacetylated 99% and does not hydrolyze CMCat all. In this paper, we describe the properties and the action pattern of the purified enzyme. Chitosanase activity was assayed by the method of 2421 Uchida et al.3) One unit is defined as the amountofenzyme required to liberate 1 /miol of reducing sugar calculated as D-glucosamineper min. The reducing sugar wasmeasured by the method of Schales and Schales.7) Chitosan (the degree of7V-deacetylation, 99%) and chitin were purchased from Cosmo Bio Co., Ltd., CMCand GlcN from Wako Pure Chemical Industries, Ltd., (GlcNAc)5 and GlcNoligomers (dimer to hexamer) from Seikagaku Kogyo Co., Ltd. The other chemicals were obtained from WakoPure Chemical Industries, Ltd. and Sigma Chemical Company. Partially 7V-deacetylated chitosans