Myers D, Imai K, Yonetani T
Department of Biochemistry and Biophysics, University of Pennsylvania School of Medicine, Philadelphia 19104.
Biophys Chem. 1990 Aug 31;37(1-3):323-40. doi: 10.1016/0301-4622(90)88032-n.
The oxygen-binding properties of hemoglobin have been studied at 600 microM protein concentration with organic phosphate, and analyzed by a series of different nonlinear least-squares analysis methods to determine whether reports of negligibly small values of the third overall Adair parameter, A3, are consequences of the data or a product of the data analysis. Data from other laboratories were analyzed as well. The single most important factor in creating a measurement that yields a small A3 is the use of equally weighted fitting in the Adair equation, while end-weighted fitting generally yields a larger A3. Endpoint extrapolation is ruled out as a major cause of abnormal A3 values. Monte Carlo simulations of the 600 microM results suggest that, if a small A3 were present, end weighting is at least as sensitive to a small A3 as equal weighting. We conclude that equally weighted fitting of the tetrameric Adair equation is unable to resolve the upper asymptote of the oxygen-binding data, resulting in an unusually small value for A3.
已在蛋白质浓度为600微摩尔的条件下，对血红蛋白与有机磷酸盐的氧结合特性进行了研究，并通过一系列不同的非线性最小二乘法分析方法进行分析，以确定关于第三总体阿代尔参数A3的值小到可忽略不计的报道，是数据的结果还是数据分析的产物。其他实验室的数据也进行了分析。得出小A3测量值的最重要因素是在阿代尔方程中使用等权重拟合，而末端加权拟合通常会得出更大的A3。排除端点外推是异常A3值的主要原因。对600微摩尔结果的蒙特卡罗模拟表明，如果存在小A3，末端加权对小A3的敏感性至少与等权重一样。我们得出结论，四聚体阿代尔方程的等权重拟合无法解析氧结合数据的上渐近线，导致A3值异常小。
