Electron transfer kinetics and morphology of cytochrome c at the biomimetic phospholipid layers

Thermodynamic and kinetic characterization of PccH, a key protein in microbial electrosynthesis processes in Geobacter sulfurreducens

“…A maximum value, within the linear range, was found to be 0.09 ± 0.02 cm s −1 (at ν = 10 mV s −1 ). The value obtained is higher compared to those of several heme electron transfer proteins, such as cytochrome c or cytochrome b 5 , in diffusional and non-diffusional regimes [22][23][24], reflecting the high efficiency of electron transfer process in PccH.…”

Direct Electron Transfer to Cytochrome c Induced by a Conducting Polymer

“…The k° value amounts to 0.049 cm s –1 , as obtained from the average value of peak separation between 0.04 and 0.7 μm (Δ E p = 62 mV, SD 2 mV). This number indicates that the electron transfer reaction is faster through the PEDOT–PSS-modified electrode than for other widely used electrodes, such as ITO, carbon materials, or chemically modified gold substrates, for which typical values on the order of 10 –3 –10 –4 cm s –1 are reported. ,− …”

“…It is known that Cyt c adsorbs strongly on conventional metal electrodes like Pt, Hg, Au or Ag 17 and conformational changes suffered by the protein (unfolding and/or denaturation) lead to slow electrontransfer kinetics 18,19 . This difficulty has been overcome by using electrode modifiers such as metal oxides, advanced carbon materials, DNA or lipid membranes [20][21][22][23][24][25][26] . In particular, the modification of surfaces with organic thin films like self-assembled monolayers (SAM), has been extensively used to manipulate the electrode surface, promoting the appropriate orientation of the protein and thus enhancing its electroactivity [27][28][29][30][31][32][33][34][35][36] .…”

“…Among redox proteins, cytochrome c (cyt c ) is probably one of the most extensively explored compounds due to its key role in the respiratory chain. − Cyt c is a water-soluble heme protein, with spherical shape and near 3 nm diameter, which has the function of accepting electrons from cyt c reductase and delivering them to cyt c oxidase in the mitochondrial inner membrane . Intensive research has shown that it is not easy to achieve DET to cyt c at solid electrode surfaces, since the redox-active heme center is wrapped by a peptide chain and protected from the solvent. , It is known that cyt c adsorbs strongly on conventional metal electrodes like Pt, Hg, Au, or Ag and conformational changes suffered by the protein (unfolding and/or denaturation) lead to slow electron-transfer kinetics. , This difficulty has been overcome by using electrode modifiers such as metal oxides, advanced carbon materials, DNA, or lipid membranes. − In particular, the modification of surfaces with organic thin films, like self-assembled monolayers (SAM), has been extensively used to manipulate the electrode surface, promoting the appropriate orientation of the protein and thus enhancing its electroactivity. − …”

The interfacial characteristic of mixed Cytochrome C/Cardiolipin Langmuir-Blodgett monolayer

“…Cyt c 与 CL 单层膜的 AFM 图分析 本实验在 20 mN/m 时采用竖直提膜法, 将单层 膜沉积在新解离的云母片上, 然后对不同量的 Cyt c 和 CL 混合单层膜的形貌图进行了 AFM 观测(图 7). 从图 7(a)可看出, 纯的 CL 单层膜整体呈现颗粒状结 构, 单层膜由许多小的颗粒紧密组装在一起, 部分 CL 分子相互聚集成一些不规则的枝状结构, 这与之前的文献报道[16] 一致, 脂膜的高度约 2 nm.图 7(b)中 可以看出, 许多白色亮的球形颗粒吸附在脂质单层 膜上(图中呈现白色亮的球形结构为蛋白分子, 之前 文献报道过 Cyt c 的浓度为 1×10 4 mol/L 时其在 AFM 图呈球形颗粒[27] ). 通过 AFM 测量其蛋白的直径为 31~110 nm, 高度为 5~22 nm (远远高于脂膜), 可知我们观察到的白色球形颗粒是蛋白的聚集体.…”