Skip Navigation

This Article
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Add to My Personal Archive
Right arrow Download to citation manager
Right arrow Request Permissions
Google Scholar
Right arrow Articles by Hoshino, E.
Right arrow Articles by Kanda, T.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Hoshino, E.
Right arrow Articles by Kanda, T.
Social Bookmarking
Add to CiteULike   Add to Connotea   Add to Del.icio.us  
What's this?

J. Biochem, 1993, Vol. 114, No. 2 230-235
© 1993 Japanese Biochemical Society

other

Mode of Action of Exo- and Endo-Type Cellulases from Irpex lacteus in the Hydrolysis of Cellulose with Different Crystallinities

Eiichi Hoshino*, Yasushi Sasaki*, Mituo Okazaki**, Kazutosi Nisizawa***,1 and Takahisa Kanda*

*Department of Chemistry and Material Engineering, Faculty of Engineering, Shinshu University Wakasato, Nagano, Nagano 380
**Department of Applied Biology, Faculty of Textile Science and Technology, Shinshu University Tokida, Ueda, Nagano 386
***Department of Fisheries, College of Agriculture and Veterinary Medicine, Nihon University Setagaya-ku, Tokyo 154

The mode of action of two highly purified cellulases of exo- and endo-types from Irpex lacteus was investigated by using pure cellulosic substrates with different crystallinities derived from cellulose I. Exo-type cellulase saccharified all celluloses more effectively than endo-type enzyme, and the saccharification activities of both cellulases similarly increased with decreasing crystallinity of cellulose. The DP-lowering activity of exo-type cellulase remained similar for celluloses with higher crystallinity, while this cellulase showed a degradation mode resembling that of the endo-type enzyme for the substrates with lower crystallinity. Compared with exo-type cellulase, endo-type cellulase remarkably decreased the DP of cellulose with higher crystallinity, while this activity was abated for cellulose with lower crystallinity. Thus, the effects of both cellulases became similar in the degradation of amorphous substrates such as H3PO4-treated cellulose. Endo-type cellulase produced several kinds of cellooligosaccharide from all kinds of cellulose used, while the product of the exo-type enzyme was only cellobiose from crystalline cellulose such as cotton and cotton linter even after a 12-h incubation period. The results indicate that each cellulase shows a typical mode of action (exo or endo) for crystalline cellulose, but that their characteristic modes of attack may change with decreasing crystallinity of cellulose.

1Present address: 10-ban-4, Kouyama-3, Nerima-ku, Tokyo 176.


Add to CiteULike CiteULike   Add to Connotea Connotea   Add to Del.icio.us Del.icio.us    What's this?




Disclaimer: Please note that abstracts for content published before 1996 were created through digital scanning and may therefore not exactly replicate the text of the original print issues. All efforts have been made to ensure accuracy, but the Publisher will not be held responsible for any remaining inaccuracies. If you require any further clarification, please contact our Customer Services Department.