Department of Chemistry and Biomolecular Science, Clarkson University, Potsdam, NY 13699- 5810, USA.
Phys Chem Chem Phys. 2022 Aug 24;24(33):19687-19692. doi: 10.1039/d2cp02112a.
Bovine serum albumin (BSA), used as a model protein, was immobilized on a buckypaper electrode by formation of covalent bonds with avidin/iminobiotin or nitroavidin/biotin complexes. pH-sensitive affinity interactions between avidin and iminobiotin or between nitroavidin and biotin allowed splitting of the affinity bonds upon pH variation, thus resulting in BSA release. Local (interfacial) pH was changed electrochemically. The pH was decreased upon electrochemical oxidation of ascorbate or increased upon electrochemical reduction of O. The local pH change resulted in the weakening of the affinity complexes, resulting in BSA release from the avidin/iminobiotin or nitroavidin/biotin systems when the pH was decreased or increased, respectively. Importantly, protein release was only observed when the number of chemical bonds with the affinity systems was decreased by blocking a part ( 50%) of the binding sites in avidin/nitroavidin with iminobiotin/biotin molecules missing the possibility of attaching the protein. Without this blocking effect, multiple bond formation with the protein preserved BSA at the electrode surface, by not allowing its release upon electrochemical pH change.
牛血清白蛋白（BSA）被用作模型蛋白，通过与亲和素/生物素或硝化物亲和素/生物素复合物形成共价键而固定在巴基纸电极上。亲和素和生物素之间或硝化物亲和素和生物素之间的 pH 敏感亲和相互作用允许在 pH 变化时拆分亲和键，从而导致 BSA 释放。局部（界面）pH 通过电化学变化。在抗坏血酸电化学氧化时 pH 降低，在 O 电化学还原时 pH 升高。局部 pH 变化导致亲和复合物减弱，导致当 pH 降低或升高时，BSA 从亲和素/生物素或硝化物亲和素/生物素系统中释放。重要的是，只有当用生物素/生物素分子阻断亲和系统的一部分（50%）结合位点从而减少与亲和系统的化学键数目时，才会观察到蛋白质释放，因为这些生物素/生物素分子缺少与蛋白质结合的可能性。没有这种阻断作用，通过不允许在电化学 pH 变化时释放蛋白质，多键形成会将 BSA 保留在电极表面上。
