Graphene Oxide Selectively Enhances Thermostability of Trypsin

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• 作者：Kai Yao ; Pengli Tan ; Yinchan Luo ; Liangzhu Feng ; Ligeng Xu ; Zhuang Liu ; Youyong Li ; Rui Peng
• 刊名：ACS Applied Materials & Interfaces
• 出版年：2015
• 出版时间：June 10, 2015
• 年：2015
• 卷：7
• 期：22
• 页码：12270-12277
• 全文大小：405K
• ISSN：1944-8252

文摘

In the past few years, graphene and its derivative, graphene oxide (GO), have been extensively studied for their applications in biotechnology. In our previous work, we reported certain PEGylated GOs (GO-PEGs) can selectively promote trypsin activity and enhance its thermostability. To further explore this, here we synthesized a series of GO-PEGs with varying PEGylation degrees. Enzymatic activity assay shows that both GO and GO-PEGs can protect trypsin, but not chymotrypsin, from thermal denaturation at high temperature. Surprisingly, the lower the PEGylation degree, the better the protection, and GO as well as the GO-PEG with the lowest PEGylation degree show the highest protection efficiency (鈭?0% retained activity at 70 掳C). Fluorescence spectroscopy analysis shows that GO/GO-PEGs have strong interactions with trypsin. Molecular Dynamics (MD) simulation results reveal that trypsin is adsorbed onto the surface of GO through its cationic residues and hydrophilic residues. Different from chymotrypsin adsorbed on GO, the active site of trypsin is covered by GO. MD simulation at high temperature shows that, through such interaction with GO, trypsin鈥檚 active site is therefore stabilized and protected by GO. Our work not only illustrates the promising potential of GO/GO-PEGs as efficient, selective modulators for trypsin, but also provides the interaction mechanism of GO with specific proteins at the nano鈥揵io interface.