Clay K L, Johnson C, Henson P
National Jewish Center for Immunology and Respiratory Medicine, Denver, CO 80206.
Biochim Biophys Acta. 1990 Oct 1;1046(3):309-14. doi: 10.1016/0005-2760(90)90246-t.
Binding of platelet activating factor (1-O-alkyl-2-O-acetyl-sn-glycero-3-phosphocholine) to albumin is an important facet of the biological activity of this phospholipid. Measurement of that binding has been hampered by the physical nature of the lipid, which made estimation of the free and bound concentrations difficult. With the use of ultracentrifugation to generate an albumin gradient and to produce a region free of protein, the successful measurement of free PAF and PAF bound to albumin was accomplished. This study has demonstrated that PAF binds to albumin at four binding sites and that the average equilibrium dissociation constant for this binding is 1.10(-7) M. Consideration of these data has led to the hypothesis that the receptor active form of PAF is the albumin-PAF complex, rather than free PAF.
血小板活化因子（1-O-烷基-2-O-乙酰基-sn-甘油-3-磷酸胆碱）与白蛋白的结合是这种磷脂生物活性的一个重要方面。该脂质的物理性质阻碍了对这种结合的测量，使得游离和结合浓度的估算变得困难。通过使用超速离心产生白蛋白梯度并产生一个无蛋白区域，成功实现了对游离PAF和与白蛋白结合的PAF的测量。这项研究表明，PAF在四个结合位点与白蛋白结合，这种结合的平均平衡解离常数为1.1×10⁻⁷ M。对这些数据的思考导致了这样一种假设，即PAF的受体活性形式是白蛋白-PAF复合物，而不是游离PAF。
