Bovine hemoglobin pseudo-crosslinked with mono(3,5-dibromosalicyl)-fumarate.
Bovine hemoglobin pseudo-crosslinked with mono(3,5-dibromosalicyl)-fumarate.
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牛血红蛋白与单（3,5-二溴水杨基）-富马酸酯假交联。
DOI：
10.1111/j.1432-1033.1990.tb19342.x
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发表时间：
1990
期刊：
影响因子：
--
通讯作者：
Gryczynski,Z
中科院分区：
文献类型：
--
作者：
Fronticelli,C;Bucci,E;Razynska,A;Sznajder,J;Urbaitis,B;Gryczynski,Z
在氧化条件下，牛血红蛋白与单（3,5-二溴水杨基）-富马酸盐反应，特异性酰化蛋白质 β 裂隙中的 EF5 赖氨酸。化学修饰在分子中引入假交联，阻碍血红蛋白分子解离成二聚体。在大鼠中测量的化学修饰的牛血红蛋白在循环中的保留时间相对于未处理的牛血红蛋白增加了五倍。 37°C、pH 7.4 下的氧亲和力 aP50= 5.4 kPa，n 值为 1.9。在相同的实验条件下，氧亲和力对阴离子和聚阴离子不敏感，而对CO2敏感。玻尔效应向碱性 pH 范围偏移 0.5-1：释放的最大质子数为 1.5 个/四聚体，类似于正常牛血红蛋白（1.8 个质子/四聚体）。使用双态Monod-Wyman-Changeux模型并固定变构常数L=105的值对结合等温线进行分析表明，T结构的氧亲和力没有改变，并且系统的低氧亲和力是由于R结构的氧亲和力的降低造成的。使用顺序阿代尔模型的分析显示了总体结合常数的修改，并表明氧化中间物质的重新分布。
Under oxygenated conditions bovine hemoglobin reacts with mono(3,5‐dibromosalicyl)‐fumarate which specifically acylates the EF5 lysines in the β‐cleft of the protein. The chemical modification introduces in the molecule a pseudo‐crosslink which hinders the dissociation of the hemoglobin molecule into dimers. Retention time in circulation of the chemically modified bovine hemoglobin, measured in the rat, is increased fivefold with respect to untreated bovine hemoglobin. The oxygen affinity at 37°C and at pH 7.4, has aP50= 5.4 kPa and a value ofn= 1.9. Under the same experimental conditions the oxygen affinity is not sensitive to anions and polyanions whereas it is sensitive to CO2. The Bohr effect is shifted toward the alkaline pH range by 0.5–1: the maximum number of protons released is 1.5/tetramer, similar to normal bovine hemoglobin (1.8 protons/tetramer). Analysis of the binding isotherms, using the two‐state Monod‐Wyman‐Changeux model and fixing the value of the allosteric constantL= 105, shows that the oxygen affinity of the T structure is not modified, and that the low oxygen affinity of the system is due to a decrease of the oxygen affinity of the R structure. Analysis using the sequential Adair model shows a modification of the overall binding constants and suggests a redistribution of the intermediate species of oxygenation.