Lapshina E A, Zavodnik I B, Ignatenko V A, Stepuro I I
Mol Biol (Mosk). 1992 Mar-Apr;26(2):315-20.
Differential scanning microcalorimetry was used to study thermal stability of the ferro- and ferriforms of hemoglobin at pH 7.4 in phosphate buffer and in buffer mixtures of methanol, ethanol, 1-propanol. Denaturation of the human hemoglobin molecule composed of four subunits was cooperative transition. The thermostability of the hemoglobin forms decreased in the order of carboxyhemoglobin (TD = 82.0 degrees C) > oxyhemoglobin (71.0 degrees C) > methemoglobin (67.0 degrees C). The aliphatic alcohols as cosolvents decreased the hemoglobin stability because of loosening the structure of the globin moiety by disturbing its hydrophobic contacts and hydrogen bonds. These alcohols reduced the oxygen affinity for hemoglobin probably due to perturbation of the R<-->T equilibrium by the decreased bulk dielectric constant of the solvent. Oxyhemoglobin and methemoglobin was converted to hemichrome by high alcohol concentrations.
采用差示扫描量热法研究了血红蛋白的亚铁和高铁形式在pH 7.4的磷酸盐缓冲液以及甲醇、乙醇、1-丙醇缓冲液混合物中的热稳定性。由四个亚基组成的人血红蛋白分子的变性是协同转变。血红蛋白各形式的热稳定性按以下顺序降低：羧基血红蛋白（Td = 82.0℃）＞氧合血红蛋白（71.0℃）＞高铁血红蛋白（67.0℃）。脂肪醇作为助溶剂会降低血红蛋白的稳定性，因为它会通过干扰球蛋白部分的疏水接触和氢键来松弛其结构。这些醇类可能由于溶剂的本体介电常数降低而扰动了R⇆T平衡，从而降低了血红蛋白对氧气的亲和力。高浓度醇会使氧合血红蛋白和高铁血红蛋白转化为半色素。
