Yakushkin V V, Tsibulsky V P
Institute of Experimental Cardiology, Russian Cardiology Complex, Moscow, 121552, Russia.
Biochemistry (Mosc). 1998 Oct;63(10):1164-71.
Binding of apoB-containing lipoproteins from unfractionated human blood sera to the immobilized bovine receptor of low density lipoproteins (LDL receptor) was studied. Peroxidase-labeled anti-human apoB antibodies were used to evaluate the lipoprotein binding. The equilibrium dissociation constant (Kd) of the interaction between apoB-containing lipoproteins from unfractionated human sera from healthy donors and the immobilized LDL receptor varied from 1 to 20 microg apoB/ml. To describe the binding of lipoproteins to the LDL receptor, a parameter of relative binding affinity (RBA) was used. RBA is inversely related to value of Kd and equal to unity for the standard serum. The RBA values for the binding of apoB-containing lipoproteins from unfractionated sera to the immobilized LDL receptor were found to correlate with the RBA values for the binding of isolated VLDL (r = 0.76, p < 0.001) and fail to correlate with the RBA values for the binding of isolated LDL. The RBA values for the binding of apoB-containing lipoproteins from unfractionated sera correlated with the RBA values for the binding of apoE-containing lipoproteins from unfractionated sera (r = 0.92, p < 0.001) and with values of triglyceride concentration in the sera (r = 0.93, p < 0.001). The RBA values for the binding of apoB-containing lipoproteins from sera of patients with FDB whose LDL were unable to bind to the LDL receptor did not significantly differ from the RBA values for the normal sera. However, the removal of VLDL from the normal sera significantly decreased the RBA values for the binding of apoB-containing lipoproteins from unfractionated sera. The results indicate that the different binding of apoB-containing lipoproteins to the immobilized LDL receptor mainly depended on the different binding of VLDL and not of LDL.
研究了来自未分级人血清中含载脂蛋白B（apoB）的脂蛋白与固定化牛低密度脂蛋白受体（LDL受体）的结合情况。使用过氧化物酶标记的抗人apoB抗体来评估脂蛋白结合。健康供体未分级人血清中含apoB的脂蛋白与固定化LDL受体之间相互作用的平衡解离常数（Kd）在1至20μg apoB/ml之间变化。为描述脂蛋白与LDL受体的结合，使用了相对结合亲和力（RBA）参数。RBA与Kd值呈负相关，对于标准血清等于1。发现未分级血清中含apoB的脂蛋白与固定化LDL受体结合的RBA值与分离的极低密度脂蛋白（VLDL）结合的RBA值相关（r = 0.76，p < 0.001），而与分离的低密度脂蛋白（LDL）结合的RBA值不相关。未分级血清中含apoB的脂蛋白结合的RBA值与未分级血清中含载脂蛋白E（apoE）的脂蛋白结合的RBA值相关（r = 0.92，p < 0.001），并与血清中甘油三酯浓度值相关（r = 0.93，p < 0.001）。来自家族性高胆固醇血症（FDB）患者血清中LDL不能与LDL受体结合的含apoB的脂蛋白结合的RBA值与正常血清的RBA值无显著差异。然而，从正常血清中去除VLDL显著降低了未分级血清中含apoB的脂蛋白结合的RBA值。结果表明，含apoB的脂蛋白与固定化LDL受体的不同结合主要取决于VLDL而非LDL的不同结合。
