氧化还原蛋白质在海藻酸钠溶液中的直接电子转移

将血红蛋白（Hb）、葡萄糖氧化酶（GOD）溶解在海藻酸钠（SA）溶液中，GOD和Hb均能在裸的玻碳电极（GCE）上发生有效和稳定的直接电子转移反应。实验结果表明，在海藻酸钠溶液中，GOD（pH=5．0）和Hb（pH=7．0）分别在裸的GCE上有一对很好的几乎对称的氧化还原峰；其式量电位（E°′）分别为一0．406V和～0．413（vs．Ag／AgCl），且不随扫速而变。GOD和Hb分别在裸的GCE表面直接电子转移的表观速率常数ks分别是（1．46±0．62）s^-1和（1．36±0．50）s^-1，在298K，其吉布斯自由能（△G）分别是79．35kJ·mol^-1和37．49kJ·mol^-1对葡萄糖和H2O2的电催化实验表明，海藻酸钠溶液形成了GCE与GOD或Hb之间实现“软接触”的生物环境，保持了Hb和GOD的生物和电化学活性。

Direct Electron Transfer of Redox Proteins in Sodium Alginate Solution

The glucose oxidase （GOD） and hemoglobin （Hb） dissolved in sodium alginate （SA） solution can achieve the direct electron transfer between proteins and glassy carbon electrode （GCE） without recourse to other materials. GOD and Hb in SA solution gave a pair of stable, well-defined, and quasi-reversible cyclic voltammetric peaks at about --0. 406 V and --0. 413 V （E°′） vs. Ag/AgCl electrode on GCE, respectively. And the peaks are located at the potential characteristic of FAD and Fe（III）/Fe（II） redox couples of the proteins, respectively. The apparent heterogeneous electron-transfer rate constants （ks） were estimated to （1.46±0.62） s^-1 and （1.36±0.50） s^-1 for GOD and Hb by voltammetry, respectively. The thermodynamics parameters （AG） of electrochemical reaction were determined to 79.35 kJ · mol ^-1 and 37.49 kJ·mol^-1 for GOD and Hb in SA solution, respectively. The responses to glucose and H202 displayed that SA solution created a biological environment, which established a ＇soft touch＇ between the electrode and protein, retaining bioactivity and electroactivity of proteins.