Mitsutomi M, Isono M, Uchiyama A, Nikaidou N, Ikegami T, Watanabe T
Department of Applied Biological Sciences, Faculty of Agriculture, Saga University, Japan.
Biosci Biotechnol Biochem. 1998 Nov;62(11):2107-14. doi: 10.1271/bbb.62.2107.
Chitosanases 33 kDa and 40 kDa in size were detected in the culture supernatant of Bacillus circulans WL-12. One of the two chitosanases, chitosanse 40 (40-kDa chitosanase) has been shown to be identical to the enzyme which has been reported previously as a beta-1,3-1,4-glucanase by Bueno et al. 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/beta-1,3-1,4-glucanase hydrolyzed both chitosan and beta-1,3-1,4-glucan with similar efficiency. However, the production of the enzyme was induced with chitosan but not by beta-1,3-1,4-glucan. Therefore, it seems possible that the major substrate of this enzyme is chitosan rather than beta-1,3-1,4-glucan. Analysis of degradation products generated from partially N-acetylated chitosan showed that chitosanase 40/beta-1,3-1,4-glucanse 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.
在环状芽孢杆菌WL-12的培养上清液中检测到了大小分别为33 kDa和40 kDa的壳聚糖酶。这两种壳聚糖酶中的一种，壳聚糖酶40（40 kDa壳聚糖酶）已被证明与Bueno等人先前报道的一种β-1,3-1,4-葡聚糖酶相同。该酶已与以前被称为纤维素酶家族D的酶一起被归类到8家族糖基水解酶中。这种名为壳聚糖酶40/β-1,3-1,4-葡聚糖酶的酶以相似的效率水解壳聚糖和β-1,3-1,4-葡聚糖。然而，该酶的产生是由壳聚糖诱导的，而不是由β-1,3-1,4-葡聚糖诱导的。因此，这种酶的主要底物似乎是壳聚糖而不是β-1,3-1,4-葡聚糖。对部分N-乙酰化壳聚糖产生的降解产物的分析表明，壳聚糖酶40/β-1,3-1,4-葡聚糖酶水解GlcN-GlcN和GlcN-GlcNAc键，但不水解GlcNAc-GlcNAc键和GlcNAc-GlcN键。该酶水解键的特异性与来自灰色链霉菌HUT6037的壳聚糖酶相似。
