Retention of Enzymatic Activity of -Amylase in the Reductive Synthesis of Gold Nanoparticles
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- 作者：Abhijit Rangnekar ; Tridib Kumar Sarma ; Atul Kumar Singh ; Jashmini Deka ; Aiyagari Ramesh ; Arun Chattopadhyay
- 刊名：Langmuir
- 出版年：2007
- 出版时间：May 8, 2007
- 年：2007
- 卷：23
- 期：10
- 页码：5700 - 5706
- 全文大小：457K
- 年卷期：v.23,no.10(May 8, 2007)
- ISSN：1520-5827
文摘
In this paper, we report the generation of Au nanoparticles (NPs), using a pure enzyme for the reduction of AuCl4-,with the retention of enzymatic activity in the complex. As a model system, 
-amylase was used to readily synthesizeand stabilize Au NPs in aqueous solution. Although several other enzymes were also pursued for the synthesis, it wasinteresting to observe that only -amylase and EcoRI could produce Au NPs. Following NP synthesis, the activityof the enzyme was retained in the Au NP--amylase complex. The presence of Au NPs and -amylase in the complexwas established by UV-visible and FT-IR spectroscopy, X-ray diffraction (XRD) and transmission electron microscopic(TEM) measurements. Our observations suggest that the presence of free and exposed S-H groups is essential in thereduction of AuCl4- to Au NPs. Structural analysis of the enzymes showed that both -amylase and EcoRI enzymeshave free and exposed S-H groups in their native form and thus are suitable for the generation of NPs, whereas theother ones used here do not have such groups. Fortuitously, the enzymatic functional group of -amylase is positionedopposite to that of the free and exposed S-H group, which makes it ideal for the production of Au NPs; binding ofthe enzyme to Au NPs via Au-S bond and also retention of the biological activity of the enzyme.
-amylase was used to readily synthesizeand stabilize Au NPs in aqueous solution. Although several other enzymes were also pursued for the synthesis, it wasinteresting to observe that only -amylase and EcoRI could produce Au NPs. Following NP synthesis, the activityof the enzyme was retained in the Au NP--amylase complex. The presence of Au NPs and -amylase in the complexwas established by UV-visible and FT-IR spectroscopy, X-ray diffraction (XRD) and transmission electron microscopic(TEM) measurements. Our observations suggest that the presence of free and exposed S-H groups is essential in thereduction of AuCl4- to Au NPs. Structural analysis of the enzymes showed that both -amylase and EcoRI enzymeshave free and exposed S-H groups in their native form and thus are suitable for the generation of NPs, whereas theother ones used here do not have such groups. Fortuitously, the enzymatic functional group of -amylase is positionedopposite to that of the free and exposed S-H group, which makes it ideal for the production of Au NPs; binding ofthe enzyme to Au NPs via Au-S bond and also retention of the biological activity of the enzyme.