Modes of action of cellulases from the gastric teeth of a gastropod Dolabella auricularia
Substrate specificity of three kinds of cellulase preparations (A, N, and Bβ) isolated from the gastric teeth of D. auricularia was investigated on various celluloic substrates. Each preparation had endo-type action, and cellulase Bβ had more random action than cellulases A and N toward CM-cellulose...
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Veröffentlicht in: | NIPPON SUISAN GAKKAISHI 1992/01/25, Vol.58(1), pp.159-163 |
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Format: | Artikel |
Sprache: | eng ; jpn |
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Zusammenfassung: | Substrate specificity of three kinds of cellulase preparations (A, N, and Bβ) isolated from the gastric teeth of D. auricularia was investigated on various celluloic substrates. Each preparation had endo-type action, and cellulase Bβ had more random action than cellulases A and N toward CM-cellulose. Kinetic constants (Km value: mg/ml) of the enzymes toward CM-cellulose and H3PO4-swollen cellulose were as follows: cellulase A, 0.3 and 1.0; cellulase N, 1.6 and 3.3; and cellulase Bβ, 5.0 and 4.2; respectively. The modes of action of cellulases A and N on cellooligosaccharides were examined. Cellulase A hydrolyzed G6 into G4+G2 and G3+G3 in a molar ratio of 4:1, and G5 into G4+G1 and G3+G2 in a molar ratio of 1:4. In the case of cellulase N, G6 was cleaved into G4+G2 and G3+G3 in a molar ratio of 8:1, and G5 was hydrolyzed into G4+G1 and G3+G2 in a molar ratio of 1:4. Synergistic action between cellulases A and Bβ in the saccharification activities toward crystalline cellulose was higher than that toward amorphous cellulose. |
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ISSN: | 0021-5392 1349-998X |
DOI: | 10.2331/suisan.58.159 |