Abstract
Chitosanases 33 kDa and 40 kDa in size were detected in the culture supernatant of Bacillus circulans WL-12. One of the two chitosanases, chitosanase 40 (40-kDa chitosanase) has been shown to be identical to the enzyme which has been reported previously as a β-1,3-1,4-glucanase by Bueno et al.1) The enzyme has been classified into family 8 glycosyl hydrolases together with the enzymes formally known as cellulase family D. This enzyme named chitosanase 40/β-1,3-1,4-glucanase hydrolyzed both chitosan and β-1,3-1,4-glucan with similar efficiency. However, the production of the enzyme was induced with chitosan but not by β-1,3-1,4-glucan. Therefore, it seems possible that the major substrate of this enzyme is chitosan rather than β-1,3-1,4-glucan. Analysis of degradation products generated from partially N-acetylated chitosan showed that chitosanase 40/β-1,3-1,4-glucanase hydrolyzes GlcN-GlcN and GlcN-GlcNAc linkages but not GlcNAc-GlcNAc nor GlcNAc-GlcN. The specificity for hydrolyzing linkages of this enzyme is similar to that of the chitosanase from S. griseus HUT6037.
