Direct electrochemistry of myoglobin and cytochrome p450cam in alternate layer-by-layer films with DNA and other polyions
Direct electrochemistry of myoglobin and cytochrome p450cam in alternate layer-by-layer films with DNA and other polyions
复制标题
DOI：
10.1021/ja9737984
复制
发表时间：
1998-05-06
影响因子：
15
通讯作者：
Rusling, JF
中科院分区：
文献类型：
--
作者：
Lvov, YM;Lu, ZQ;Rusling, JF
用化学吸附的巯基丙磺酸包覆的金电极上交替逐层吸附多离子，得到了稳定的含有肌红蛋白和细胞色素P450(CaM)的电活性多层膜。金电极与蛋白质之间直接的、可逆的电子交换涉及到血红素Fe-III/Fe-II氧化还原对。在溶液中有氧气的情况下，电子也转移到这些蛋白质的Fe-II-O-2络合物中，这是氧化酶催化的关键步骤。Mb的膜组装是通过顺序吸附聚苯乙烯磺酸(PSS)、DNA或聚二甲基二烯丙基氯化铵(PDDA)完成的。细胞色素P450(Cam)与PSS或PDDA层组装。对同一薄膜的石英晶体微天平和伏安研究允许对电活性和非电活性蛋白质进行定量。在pH为5.5时，所有膜中的第一个蛋白单层都是完全电活性的。第二个单分子层增加了30-40%的氧化还原活性，但额外的蛋白质层不与电极沟通。使用不同的膜构建策略，Mb单分子膜也被放置在与电极的0.5、1.8和3.8 nm的距离处。在0.5 nm处有完全的电活性，在1.8和3.8 nm处有大约70-80%的电活性。结果表明，蛋白质层和非蛋白质层的部分混合有可能增强电子传递。含Mb和细胞色素P450(CaM)的聚离子膜对好氧溶液中的苯乙烯环氧化具有类酶催化活性。
Alternate layer-by-layer polyion adsorption onto gold electrodes coated with chemisorbed mercaptopropanesulfonic acid gave stable, electroactive multilayer films containing the proteins myoglobin and cytochrome P450(cam). Direct, reversible, electron exchange between gold electrodes and proteins involved heme Fe-III/Fe-II redox couples. With oxygen in solution, electrons were also transferred to the Fe-II-O-2 complexes of these proteins, a key step for oxidative enzyme catalysis. Film assembly for Mb was done by sequential adsorption with poly(styrenesulfonate) (PSS), DNA, or poly(dimethyl diallyl) ammonium chloride (PDDA). Cyt P450(cam) was assembled with layers of PSS or PDDA. Quartz crystal microbalance and voltammetric studies on the same films allowed quantitation of electroactive and nonelectroactive protein. At pH 5.5, the first protein monolayer in all films was fully electroactive. A second monolayer added 30-40% redox activity, but additional protein layers did not communicate with the electrode. Using various film construction strategies, Mb monolayers were also placed at distances from the electrodes of 0.5; 1.8, and 3.8 nm. Full electroactivity was found at 0.5 nm, and about 70-80% electroactivity at 1.8 and 3.8 nm. Results suggest the possibility of enhanced electron transport by partial intermixing of protein and nonprotein layers. Polyion films containing Mb and cyt P450(cam) were active for enzyme-like catalysis of styrene epoxidation in aerobic solutions.