Trichoderma reesei cellulases and their core domains in the hydrolysis and modification of chemical pulp
Trichoderma reesei cellulases and their core domains in the hydrolysis and modification of chemical pulp
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DOI：
10.1023/a:1009280109519
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发表时间：
2000-06-01
期刊：
影响因子：
5.7
通讯作者：
Buchert, J
中科院分区：
文献类型：
--
作者：
Suurnäkki, A;Tenkanen, M;Buchert, J
采用分离的纤维素和漂白的化学浆，比较了单组分里氏木霉内切葡聚糖酶（EG I、EG II; EC 3.2.1.4）和纤维素生物水解酶（CBH I、CBH II; EC 3.2.1.91）及其核心蛋白的作用。完整酶中纤维素结合域（CBD）的存在不影响其对可溶性底物的作用。在不溶性分离纤维素和化学浆的情况下，CBD的存在增强了纤维素的酶解。CBD对纤维素生物水解酶的作用更明显，主要水解结晶纤维素，而对内切葡聚糖酶的作用更明显，内切葡聚糖酶水解无定形纤维素。完整酶和相应核心蛋白处理对纸浆性能（即PFI精炼后的粘度和强度）的影响相同，表明完整纤维素酶中CBD的存在主要影响纤维素水解水平，而对T. reesei纤维素酶在纸浆中的作用方式影响较小。用完整的内切葡聚糖酶处理的漂白化学纸浆比用相应的核心蛋白处理的漂白化学纸浆的可打性更好，这表明内切葡聚糖酶中CBD的存在可能对纸浆性能产生有益的影响。
The action of monocomponent Trichoderma reesei endoglucanases (EG I, EG II; EC 3.2.1.4) and cellobiohydrolases (CBH I, CBH II; EC 3.2.1.91) and their core proteins was compared using isolated celluloses and bleached chemical pulp. The presence of cellulose binding domain (CBD) in the intact enzymes did not affect their action against soluble substrates. In the case of insoluble isolated celluloses and the chemical pulp the presence of CBD enhanced the enzymatic hydrolysis of cellulose. The effect of CBD was more pronounced in the cellobiohydrolases, hydrolysing mainly crystalline cellulose, than in the endoglucanases which were more efficient in hydrolysing amorphous cellulose. The pulp properties measured, that is, viscosity and strength after PFI refining, were equally affected by the treatment with intact enzymes and corresponding core proteins, suggesting that the presence of CBD in intact cellulases affects mainly the cellulose hydrolysis level and less the mode of action of T. reesei cellulases in pulp. The better beatability of the bleached chemical pulp treated with intact endoglucanases than that treated with the corresponding core proteins suggests that the presence of CBD in endoglucanases could, however, result in beneficial effects on pulp properties.