Enzyme deactivation during cellulose hydrolysis
Enzyme deactivation during cellulose hydrolysis
复制标题
纤维素水解过程中酶失活
DOI：
10.1002/bit.260200607
复制
发表时间：
1978
影响因子：
3.8
通讯作者：
M. Mangat
中科院分区：
文献类型：
--
作者：
J. Howell;M. Mangat
绿色木霉纤维素酶水解纤维素约25小时后达到一个平台。如果初始酶与底物的比例较低，则将底物重悬于新鲜酶中或添加酶导致进一步的高速率水解。如果初始比率高，则不会发生这种情况。前者水解率可达75%以上，后者水解率低于60%。提出了一个模型，假定吸附的酶底物复合物，阻止进一步水解的失活，它被发现拟合数据很好。该模型有五个参数，其中四个参数可以通过图形方法进行检验，并且所有参数都具有物理意义。使用数值积分和参数优化，通过非线性最小二乘最小化FORTRAN计算机程序估计参数。该模型被用来预测的再悬浮数据，粉末酶添加数据，纤维二糖添加数据，和纤维素添加数据的偏差进行了讨论。结果发现，平均值可用于五个参数中的四个，而第五个（初始酶浓度）与独立测量值（如滤纸活性或蛋白质浓度）不相关。
Hydrolysis of cellulose by Trichoderma viride cellulase reached a plateau after some 25 hr. If the initial enzyme‐to‐substrate ratio was low, resuspension of substrate in fresh enzyme or addition of enzyme resulted in further high rate hydrolysis. This did not occur if the initial ratio was high. Over 75% hydrolysis might be achieved in the former case, while less than 60% in the latter. A model postulating inactivation of adsorbed enzyme–substrate complex which blocked further hydrolysis was proposed, and it was found to fit the data well. The proposed model had five parameters, four of which could be checked by graphical methods, and all of which had physical meanings. The parameters were estimated by a nonlinear least‐squares minimization FORTRAN computer program, using numerical integration and optimization of the parameters. The model was used to predict the resuspension data, powdered enzyme addition data, cellobiose addition data, and cellulose addition data; the deviations from the model are discussed. It was found that average values could be used for four out of the five parameters, while the fifth (initial enzyme concentration) did not correlate with independent measurements such as the filter paper activity or protein concentration.