Melittin lysis of red cells
Melittin lysis of red cells
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DOI：
10.1007/bf01870697
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发表时间：
2005
期刊：
影响因子：
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通讯作者：
M. Tosteson;S. Holmes;M. Razin;D. Tosteson
中科院分区：
文献类型：
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作者：
M. Tosteson;S. Holmes;M. Razin;D. Tosteson
本文描述了旨在探索人类红细胞膜和蜂毒肽，蜂毒的主要成分之间的相互作用的实验。我们发现蜂毒肽在室温下与悬浮在等渗NaCl中的人红细胞膜结合，表观解离常数为3×10− 8，最大结合容量为1.8× 107个分子/细胞。当约1%的蜂毒肽结合位点被占据时，可以观察到细胞裂解，并且所占据的总位点的分数的逐渐的进一步增加以分级的方式导致逐渐更大的裂解。当有约2× 106个分子结合到细胞膜上时，发生50%的溶解。对于任何特定程度的蜂毒肽结合，裂解在最初几分钟内迅速进行，但随后减慢并停止，使得细胞暴露于蜂毒肽一小时后不再发生裂解。蜂毒肽对红细胞的分级裂解是由于一些细胞的完全裂解，因为在经历分级蜂毒肽裂解的悬浮液中存活的完整细胞的密度和血红蛋白含量与在加入蜂毒肽之前在相同细胞中观察到的值相似。在分级蜂毒肽裂解中存活的细胞具有增加的Na和减少的K，与蜂毒肽结合位点的占据程度成比例。与溶解一样，在暴露于蜂毒素的最初几分钟内，Na积累和K损失迅速进行，但随后停止，使得细胞的Na、K和血红蛋白含量在第一个小时后保持恒定。裂解和阳离子运动的这些动力学特征表明，蜂毒肽仅在相互作用开始后的最初几分钟内改变红细胞膜的渗透性。通过Nomarsky光学直接观察细胞，发现它们在首次观察到这些形态变化后的10至30秒内形成圆齿、肿胀和溶解。总之，这些结果与蜂毒素在室温下通过胶体渗透机制产生人红细胞溶解的想法一致。
This paper describes experiments designed to explore interactions between human red blood cell membranes and melittin, the main component of bee venom. We found that melittin binds to human red cell membranes suspended in isotonic NaCl at room temperature, with an apparent dissociation constant of 3×10−8mand maximum binding capacity of 1.8×107molecules/cell. When about 1% of the melittin binding sites are occupied, cell lysis can be observed, and progressive, further increases in the fraction of the total sites occupied lead to progressively greater lysis in a graded manner. 50% lysis occurs when there are about 2×106molecules bound to the cell membrane. For any particular extent of melittin binding, lysis proceeds rapidly during the first few minutes but then slows and stops so that no further lysis occurs after one hour of exposure of cells to melittin. The graded lysis of erythrocytes by melittin is due to complete lysis of some of the cells, since both the density and the hemoglobin content of surviving, intact cells in a suspension that has undergone graded melittin lysis are similar to the values observed in the same cells prior to the addition of melittin. The cells surviving graded melittin lysis have an increased Na and reduced K, proportional to the extent of occupation of the melittin binding sites. Like lysis, Na accumulation and K loss proceed rapidly during the first few minutes of exposure to melittin but then stops so that Na, K and hemoglobin content of the cells remain constant after the first hour. These kinetic characteristics of both lysis and cation movements suggest that melittin modifies the permeability of the red cell membrane only for the first few minutes after the start of the interaction. Direct observation of cells by Nomarsky optics revealed that they crenate, become swollen and lyse within 10 to 30 sec after these changes in morphology are first seen. Taken together, these results are consistent with the idea that melittin produces lysis of human red cells at room temperature by a colloid osmotic mechanism.