Essner Jeremy B, McCay Richard N, Smith Ii Chip J, Cobb Stephen M, Laber Charles H, Baker Gary A
Department of Chemistry, University of Missouri-Columbia, Columbia, MO 65211, USA.
J Mater Chem B. 2016 Mar 28;4(12):2163-2170. doi: 10.1039/c6tb00052e. Epub 2016 Mar 4.
We describe a straightforward tactic to boost the inherently low peroxidase-like activity of the heme-protein equine cytochrome c (cyt c) following its electrostatic assembly onto the carbon nanodot surface. This represents the first time that carbon nanodot interaction has been demonstrated to switch a protein into a high-performance enzyme for speeding up a reaction it was not evolved to catalyze. The dramatic enhancement in peroxidase-like activity stems in part from favorable local perturbations within the heme microenvironment of cyt c which are influenced by the chemistry presented at the carbon dot surface. That is, the observed peroxidase activity is clearly moderated by the choice of molecular precursors used to prepare the carbon dots, a choice which ultimately determines the surface charges present. An exceptional catalytic efficiency (k/K) of 8.04 (±1.74) × 10 M s was determined for carbon dot/cyt c co-assemblies, close to the theoretical diffusion-controlled limit. Notably, the activity of the carbon dot/cyt c assembly can be switched off simply by increasing the ionic strength which results in dissociation into non-catalytic components.
我们描述了一种直接的策略，在将血红素蛋白马细胞色素c（cyt c）静电组装到碳纳米点表面后，提高其固有的低过氧化物酶样活性。这是首次证明碳纳米点相互作用能将一种蛋白质转变为一种高性能酶，以加速其未进化来催化的反应。过氧化物酶样活性的显著增强部分源于cyt c血红素微环境内有利的局部扰动，这受到碳点表面化学性质的影响。也就是说，观察到的过氧化物酶活性显然受到用于制备碳点的分子前体选择的调节，这一选择最终决定了表面电荷的存在。碳点/cyt c共组装体的催化效率（k/K）为8.04（±1.74）×10 M s，接近理论扩散控制极限。值得注意的是，只需增加离子强度，碳点/cyt c组装体的活性就可以关闭，这会导致其解离成无催化作用的组分。
