Vandegriff K D, McCarthy M, Rohlfs R J, Winslow R M
Department of Medicine, School of Medicine, University of California, San Diego 92161, USA.
Biophys Chem. 1997 Nov;69(1):23-30. doi: 10.1016/s0301-4622(97)00079-3.
Colloid osmotic pressures of hemoglobin solutions containing unmodified, intramolecularly cross-linked, intermolecularly polymerized, or polyethylene glycol (PEG) surface-conjugated hemoglobin have been measured to determine their macromolecular solution properties. Tetrameric and polymeric hemoglobins show nearly ideal solution behavior: whereas, hemoglobins conjugated to PEG have significantly higher colloid osmotic activity and exhibit solution non-ideality. From these studies, the average calculated molecular weights are 65.300 +/- 3500 for unmodified and intramolecularly cross-linked hemoglobin tetramers, 156,000 for ring-opened raffinose polymerized human hemoglobin, 97,000 for pyridoxalated human hemoglobin conjugated to a carboxy-PEG polymer, and 117,000 for bovine hemoglobin conjugated to a methoxy-PEG polymer. The calculated radius of gyration for tetrameric hemoglobins is 2.9 +/- 0.2 nm compared to 4.9 nm for the polymerized hemoglobin, and 7.2 and 14.1 nm for the human and bovine PEG-conjugated hemoglobins, respectively. Exclusion volumes are calculated to be 823 +/- 148 nm3 for tetramers, 4000 nm3 for polymers, and 13,000 nm3 and 94,000 nm3 for human and bovine PEG-conjugated hemoglobins, respectively. These studies show that polyethylene glycol conjugated to surface amino groups greatly increases the effective macromolecular size of hemoglobin in solution.
已对含有未修饰、分子内交联、分子间聚合或聚乙二醇（PEG）表面共轭血红蛋白的血红蛋白溶液的胶体渗透压进行了测量，以确定其大分子溶液性质。四聚体和聚合血红蛋白表现出近乎理想的溶液行为：而与PEG共轭的血红蛋白具有显著更高的胶体渗透活性，并表现出溶液非理想性。通过这些研究，未修饰和分子内交联血红蛋白四聚体的平均计算分子量为65300±3500，环化棉子糖聚合人血红蛋白为156000，与羧基PEG聚合物共轭的吡哆醛化人血红蛋白为97000，与甲氧基PEG聚合物共轭的牛血红蛋白为117000。四聚体血红蛋白的计算回转半径为2.9±0.2nm，而聚合血红蛋白为4.9nm，人源和牛源PEG共轭血红蛋白分别为7.2nm和14.1nm。计算得出四聚体的排阻体积为823±148nm³，聚合物为4000nm³，人源和牛源PEG共轭血红蛋白分别为13000nm³和94000nm³。这些研究表明，与表面氨基共轭的聚乙二醇极大地增加了溶液中血红蛋白的有效大分子尺寸。
