摘要
研究了细胞色素Ｃ（Ｃｙｔ．Ｃ）在一种新的电子转移促进剂４，６－二甲基－２－巯基嘧啶修饰微带金电极（ＤＭＭＰ／Ａｕ）上的氧化还原热力学；求得Ｃｙｔ．Ｃ在ＤＭＭＰ／Ａｕ电极上电化学反应的标准电极电位Ｅ￣０＇、熵变△Ｓ￣０、焓变△ＩＩ０及Ｇｉｂｂｓ自由能的改变△Ｇ￣０值分别为：０．２７２Ｖ（ｖｓ．ＮＨＥ）、－１２３．７Ｊ·ｍｏｌ￣（－１）·Ｋ￣（－１）、－６３．１ｋＪ·ｍｏｌ￣（－１）和－２６．２ｋＪ·ｍｏｌ￣（－１）（２５℃，ｐＨ＝７．０）；同时，探讨了温度及ｐＨ值对Ｃｙｔ．Ｃ电极反应热力学参数的影响．实验表明，碱性条件下Ｅ￣０＇随温度的变化表现出与中性及弱酸性条件下不同的规律．
The redox thermodynamics of cytochrome C at a 4, 6-dimethyl-mercaptopyrimidine(DMMP), a new electron transfer promoter of cytochrome C, modified microband gold electrode(DMMP/Au)was investigated by cyclic voltammetry. The thermodynamic param eters of the electron-transfer reaction of cytochrome C at DMMP/Au electrode were estimated. The normal potential E0', the changes of entropy,enthalpy and Gibbs free energy,△S￣0,△H￣0 and △G￣0, for cytochrome C at 25℃ and pH 7.0 were 0.272 V(vs. NHE),-123.7 J· mol￣(-1)·K￣(-1),-63.1 kJ·mol￣(-1) and -26.2kJ·mol￣(-1), respectively. The effects of temperature and pH on the thermodynamic parameters of cytochrome C were discussed. The E￣0' vs.T plot shows remarkable biphasic character in an alkaline solution with a turning point at ca.45℃, whereas in an acid or neutral solution the E￣0' values changed monotonically with temperature.
出处
《高等学校化学学报》
SCIE
EI
CAS
CSCD
北大核心
1995年第1期31-34,共4页
Chemical Journal of Chinese Universities
基金
国家自然科学基金
国家教育委员会博士点基金
青年基金
关键词
微电极
金电极
细胞色素C
二甲基
巯基嘧啶
Microelectrode,Microband gold electrode,Cytochrome C,4,6-Dimethyl-2-Mercaptopyrimidine, Thermodynamics
