Cello-oligosaccharide hydrolysis by cellobiohydrolase II from Trichoderma reesei

Vesa Harjunpää, Anita Teleman, Anu Koivula, Laura Ruohonen, Tuula Teeri, Olle Teleman, Torbjörn Drakenberg

Research output: Contribution to journalArticleScientificpeer-review

60 Citations (Scopus)

Abstract

The hydrolysis of soluble cello‐oligosaccharides, with a degree of polymerisation of 4–6, catalysed by cellobiohydrolase II from Trichoderma reesei was studied using 1H‐NMR spectroscopy and HPLC. The experimental progress curves were analysed by fitting numerically integrated kinetic equations, which provided cleavage patterns and kinetic constants for each oligosaccharide. This analysis procedure accounts for product inhibition and avoids the initial slope approximation. No glucose was detected at the beginning of the reaction indicating that only the internal glycosidic linkages are attacked. For cellotetraose only the second glycosidic linkage was cleaved. For cellopentaose and cellohexaose the second and the third glycosidic linkage from the non‐reducing end were cleaved with approximately equal probability. The degradation rates of these cello‐oligosaccharides, 1–12 s−1 at 27°C, are about 10–100 times faster than for the 4‐methylumbelliferyl substituted analogs or for cellotriose. No intermediate products larger than cellotriose were released. The degradation rate for cellotetraose were higher than its off‐rate, which accounts for the processive degradation of cellohexaose. A high cellohexaose/enzyme ratio caused slow reversible inactivation of the enzyme.
Original languageEnglish
Pages (from-to)584-591
Number of pages8
JournalEuropean Journal of Biochemistry
Volume240
Issue number3
DOIs
Publication statusPublished - 1996
MoE publication typeA1 Journal article-refereed

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