Reversible, selective immobilization of nuclease P₁ from a crude enzyme solution on a weak base anion resin activated by polyethylenimine

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• 作者：Bingbing Li ; Yong Chen ; Zhi Cao ; Huanqing Niu ; Dong Liu ; Ying He ; Xiaochun Chen ; Jinglan Wu ; Jingjing Xie ; Wei Zhuang ; Hanjie Ying
• 关键词：Adsorption ; Nuclease P1 ; Penicllium citrinum ; Polyethylenimine ; Reversible immobilization
• 刊名：Journal of Molecular Catalysis B: Enzymatic
• 出版年：March, 2014
• 年：2014
• 卷：101
• 期：Complete
• 页码：92-100
• 全文大小：2135 K

文摘

The reversible immobilization of crude nuclease P₁ fermented by Penicllium citrinum and used without further purification was performed via adsorption on a weak base anion resin activated by polyethylenimine (PEI). The immobilization conditions, including PEI concentration, the amount of support, the immobilization time, and the reusability of the PEI-activated resin were investigated. The results have shown that the PEI-activated resin has the capability of selectively adsorbing nuclease P₁. Subsequently, the functional properties of the immobilized nuclease P₁ were studied and compared to those of the free enzyme. The apparent K_m value for immobilized nuclease P₁ on the activated resin (15.31 g L^鈭?) was about 4.41-fold higher than that of the free enzyme (3.47 g L^鈭?), and the apparent V_max value of the immobilized enzyme (530 U g^鈭?) was about 3.9-fold less than that of the free enzyme (2082 U mL^鈭?). The optimum temperature was observed to be 70 掳C, 15 掳C higher than that of the free enzyme. The optimum pH was the same for both free and immobilized nuclease P₁ (pH 5.0). The apparent activation energies (E_a) of the free and immobilized nuclease P₁ were 163.09 kJ mol^鈭? and 156.32 kJ mol^鈭?, respectively, implying that the catalytic efficiency of the immobilized enzyme was restricted by mass-transfer rather than kinetic limitations.