- 著者
- Naoki Shirasaka Koichi Harazono Ryota Nakahigashi Keigo Mitsui Jun Tanaka Sayaka Tanazawa Masaru Mitsutomi Takayuki Ohnuma
- 出版者
- The Japanese Society of Applied Glycoscience
- 雑誌
- Journal of Applied Glycoscience (ISSN:13447882)
- 巻号頁・発行日
- vol.66, no.3, pp.83-88, 2019-08-20 (Released:2019-08-28)
- 参考文献数
- 29
- 被引用文献数
- 2
We characterized SaHEX, which is a glycoside hydrolase (GH) family 20 exo-β-N-acetylhexosaminidase found in Streptomyces avermitilis. SaHEX exolytically hydrolyzed chitin oligosaccharides from their non-reducing ends, and yielded N-acetylglucosamine (GlcNAc) as the end product. According to the initial rate of substrate hydrolysis, the rates of (GlcNAc)3 and (GlcNAc)5 hydrolysis were greater than the rates for the other oligosaccharides. The enzyme exhibited antifungal activity against Aspergillus niger, which was probably due to hydrolytic activity with regard to chitin in the hyphal tips. Therefore, SaHEX has potential for use in GlcNAc production and food preservation.
- 著者
- Tomoyo Nishihira Asami Miyano Takayuki Ohnuma Takeshi Gotoh Saori Takahashi Kazue Narihiro Kazuhiko Yamashita Tamo Fukamizo
- 出版者
- 日本応用糖質科学会
- 雑誌
- Journal of Applied Glycoscience (ISSN:13447882)
- 巻号頁・発行日
- vol.61, no.4, pp.113-116, 2014 (Released:2014-11-20)
- 参考文献数
- 16
- 被引用文献数
- 2
A simple turbidimetric assay using chitin nanofiber as the substrate was employed to measure chitinase activity. The higher dispersive properties of chitin nanofibers enabled the degradation of chitin to be monitored turbidimetrically. When non-processive chitinases, a family GH18 chitinase from the tobacco plant and a GH19 chitinase from rye seeds, were added to the β-chitin nanofiber suspension, no significant changes were observed in the turbidity of the suspension, however, the amounts of reducing sugars produced were significantly high and small amounts of GlcNAc and (GlcNAc)2 were detected by HPLC in the reaction mixture. However, the addition of a processive family GH18 chitinase, Serratia marcescence chitinase B or chitinase from Autographa californica multiple nucleopolyhedrovirus, resulted in a significant decrease in the turbidity of the chitin nanofiber suspension, and produced larger amounts of reducing sugars including GlcNAc and (GlcNAc)2. The rate of decreases in turbidity was clearly dependent upon the enzyme concentration. We concluded that the turbidimetric assay using β-chitin nanofibers as the substrate was useful for measuring the activities of processive chitinases.