Influence of pH and ionic strength on the adsorption, leaching and activity of myoglobin immobilized onto ordered mesoporous silicates
Influence of pH and ionic strength on the adsorption, leaching and activity of myoglobin immobilized onto ordered mesoporous silicates
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DOI：
10.1016/j.molcatb.2007.07.005
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发表时间：
2007-11-16
影响因子：
--
通讯作者：
Hodnett, B. K.
中科院分区：
文献类型：
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作者：
Essa, H.;Magner, E.;Hodnett, B. K.
肌红蛋白已固定到不同的有序介孔硅酸盐。研究了pH值对吸附、浸出和活性的影响。结果表明，在pH 6.5时吸附量最大，刚好低于蛋白质的等电点（7 - 7.3）。在不同的pH值下，增加离子强度对吸附曲线没有影响。的吸附是合理的，在酶和二氧化硅表面之间的局部静电力作用，以及疏水相互作用接近蛋白质等电点，而在低pH值的全局电荷引起蛋白质-蛋白质排斥和在高pH值的酶-二氧化硅排斥。在pH 4下浸出的固定化肌红蛋白量较高，而在pH 6.5下浸出的量较低。固定到SBA- 15上的肌红蛋白的催化活性在pH 6.5下显示出最佳活性，与游离形式的pH 5相比。(c)2007 Elsevier B. V.保留所有权利。
Myoglobin has been immobilized onto different ordered mesoporous silicates. The effect of the pH on the adsorption, leaching and activity was studied. The results showed that the maximum amount of protein was adsorbed at a pH 6.5, just below the protein isoelectric point (7 - 7.3). There was no effect of increasing ionic strength on the adsorption profile at different pH values. The adsorption is rationalized in terms of local electrostatic forces acting between the enzyme and the silica surface as well as hydrophobic interactions close to the protein isoelectric point, whereas at low pH the global charges give rise to protein - protein repulsion and at high pH enzyme - silica repulsion. Higher amounts of immobilized myoglobin were leached at a pH 4, while lower amounts were leached at pH 6.5. The catalytic activity of myoglobin immobilized onto SBA- 15 showed optimal activity at a pH 6.5 in comparison to a pH of 5 for the free form. (c) 2007 Elsevier B.V. All rights reserved.