De Sanctis G, Maranesi A, Ferri T, Poscia A, Ascoli F, Santucci R
Department of Biology M.C.A., University of Camerino, Italy.
J Protein Chem. 1996 Oct;15(7):599-606. doi: 10.1007/BF01886742.
The effect of glycerol on the structure and redox properties of horse heart cytochrome c was investigated by absorption spectroscopy, circular dichroism, and dc cyclic voltammetry techniques. The results show that the organic solvent increases the alpha-helix structure of the protein and induces slight changes at the active-site environment: however, the overall tertiary structure does not appear to be significantly perturbed. Glycerol stabilizes cytochrome c, the free energy of denaturation (delta G0) being approximately 0.7 kcal/mol larger than that determined in phosphate buffer under the same conditions, and influences the heterogeneous electron transfer kinetics at a chemically modified gold electrode: on the other hand, the redox potential of the protein is unaltered. On the whole, the results obtained indicate that glycerol acts as a suitable stabilizing agent of cytochrome c, which is of interest for application in biotechnology: the organic solvent does not alter the tertiary structure significantly or the redox properties of the protein. This has to be interpreted not only in terms of the glycerol-induced solvent ordering around the protein surface, but also as due to the specific features of the protein matrix.
通过吸收光谱法、圆二色光谱法和直流循环伏安法技术研究了甘油对马心脏细胞色素c结构和氧化还原性质的影响。结果表明，有机溶剂增加了蛋白质的α-螺旋结构，并在活性位点环境中引起轻微变化：然而，整体三级结构似乎并未受到显著扰动。甘油使细胞色素c稳定，变性自由能（ΔG0）比在相同条件下磷酸盐缓冲液中测定的值大约大0.7千卡/摩尔，并影响化学修饰金电极上的异质电子转移动力学：另一方面，蛋白质的氧化还原电位未改变。总体而言，所获得的结果表明甘油是细胞色素c的合适稳定剂，这在生物技术应用中具有重要意义：有机溶剂不会显著改变蛋白质的三级结构或氧化还原性质。这不仅要从甘油诱导蛋白质表面周围溶剂有序化的角度来解释，还要归因于蛋白质基质的特定特征。
