Modulating enzymatic activity in the presence of gold nanoparticles
Modulating enzymatic activity in the presence of gold nanoparticles
复制标题
DOI：
10.1039/c2ra20056b
复制
发表时间：
2012-01-01
期刊：
影响因子：
3.9
通讯作者：
Chattopadhyay, Arun
中科院分区：
文献类型：
--
作者：
Deka, Jashmini;Paul, Anumita;Chattopadhyay, Arun
枸橼酸稳定金纳米粒子（cito - au NPs）的存在显著提高了α -淀粉酶的比活性，这种活性也可以通过改变酶的浓度来调节，同时保持NP浓度不变。此外，NPs存在时酶的Michaelis-Menten行为的最低浓度（0.175 μ g mL(-1)）远小于NPs不存在时。在较高的蛋白质浓度下，酶活性单调下降，直至达到与游离酶几乎相同的水平，而在所有浓度下均表现出Michaelis-Menten动力学。透射电子显微镜（TEM）和基于动态光散射（DLS）的粒径分析表明，随着蛋白质浓度的增加，NPs的团聚现象增加。这些结果是基于一个模型来解释的，该模型考虑了与NP结合的酶的存在和可用于增强催化的酶，与NP结合但由于被埋在团块内而不可用的酶和游离酶。
The presence of citrate-stabilized gold nanoparticles (cit-Au NPs) significantly enhanced the specific activity of alpha-amylase, which could also be modulated by varying the concentration of the enzyme, while keeping the NP concentration constant. Also, the lowest concentration (0.175 mu g mL(-1)) at which the Michaelis-Menten behavior of the enzyme could clearly be observed in the presence of NPs was much less than that in their absence. At higher protein concentrations the activity decreased monotonically until it reached nearly the same as that of free enzyme, while exhibiting Michaelis-Menten kinetics at all concentrations. Transmission electron microscopy (TEM) and dynamic light scattering (DLS) based particle size analyses indicated increased agglomeration of the NPs with increased protein concentration. The results have been explained based on a model which considered the presence of enzyme bound to NP and that available for enhanced catalysis, enzyme bound to NP but unavailable due to being buried inside the agglomerate and the free enzyme.