Institute of Biophysics, Academy of Sciences of the Czech Republic, Kralovopolska 135, 612 65 Brno, Czech Republic.
Bioelectrochemistry. 2012 Dec;88:8-14. doi: 10.1016/j.bioelechem.2012.04.005. Epub 2012 May 3.
Glycoproteins participate in various biological events, including disease progression. Currently, there is a pressing need for development of new simple and inexpensive methods for glycoprotein carbohydrate component (mostly oligosaccharides, OLSs) analysis and electrochemical methods were little applied in their analysis. Polysaccharides and OLS were long time considered as electroinactive compounds. We show that OLS adducts with six-valent osmium complexes are electroactive and can be determined at mercury and carbon electrodes. Adducts of OLSs with complex of Os(VI) with N,N,N',N'-tetramethylethylenediamine (tmen) can be prepared by mixing of OLS with [Os(VI)tmen] either at 37°C overnight or at 75°C in 10-15min. We modified 3α,6α-mannopentaose (MPO), stachyose and γ-cyclodextrin with [Os(VI)tmen]. The OLS adducts produced CV redox couples at hanging mercury drop electrode (HMDE) and at pyrolytic graphite electrode (PGE). 6nM MPO was determined by conventional adsorptive stripping at HMDE with RSD 5.3% directly in the reaction mixture. Similar determination at PGE was much less sensitive. Using adsorptive transfer (ex situ) stripping at PGE, μL volumes of OLS were sufficient for the analysis. Protein glycosylation stands at present in focus of medicinal chemistry because of its importance in various diseases and their diagnostics. Our paper represents first steps toward application of electrochemical methods in biomedical analysis of OLS.
糖蛋白参与各种生物事件，包括疾病进展。目前，迫切需要开发新的简单、廉价的糖蛋白碳水化合物成分（主要是寡糖，OLSs）分析方法，而电化学方法在其分析中应用较少。多糖和 OLS 长期以来被认为是电惰性化合物。我们表明，六价锇配合物的 OLS 加合物是电活性的，可以在汞和碳电极上测定。OLS 与六价锇与 N，N，N'，N'-四甲基乙二胺（tmen）的配合物的加合物可以通过将 OLS 与[Os（VI）tmen]混合在 37°C 下过夜或在 75°C 下在 10-15 分钟内制备。我们用[Os（VI）tmen]修饰了 3α，6α-甘露五糖（MPO）、棉子糖和γ-环糊精。OLS 加合物在悬汞滴电极（HMDE）和热解石墨电极（PGE）上产生 CV 氧化还原偶。在反应混合物中直接在 HMDE 上通过常规吸附性剥离测定 6nM MPO，相对标准偏差为 5.3%。在 PGE 上进行类似的测定灵敏度要低得多。使用 PGE 上的吸附转移（异位）剥离，只需微升体积的 OLS 即可进行分析。由于其在各种疾病及其诊断中的重要性，蛋白质糖基化目前成为药物化学的焦点。我们的论文代表了电化学方法在 OLS 生物医学分析中应用的第一步。
