KINETICS AND MECHANISM OF HEMOLYSIS INDUCED BY MELITTIN AND BY A SYNTHETIC MELITTIN ANALOG
KINETICS AND MECHANISM OF HEMOLYSIS INDUCED BY MELITTIN AND BY A SYNTHETIC MELITTIN ANALOG
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DOI：
10.1016/s0006-3495(82)84681-x
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发表时间：
1982-01-01
影响因子：
3.4
通讯作者：
KEZDY, FJ
中科院分区：
文献类型：
--
作者：
DEGRADO, WF;MUSSO, GF;KEZDY, FJ
从蜂毒中提取的细胞毒性肽，蜂毒素和它的合成肽类似物在双相过程中溶解人红细胞。研究了在0.30 M蔗糖、0.01 M磷酸钠、pH 7.30、4℃条件下的裂解动力学。我们的研究结果表明，蜂窝蜂素迅速结合到红细胞膜的外表面，表面结合的单体产生短暂的开口，大约40个血红蛋白分子可以通过这个开口逃脱。同时，蜂毒蛋白失去了影响这一过程的能力，可能是通过双分子层的易位。该工艺的半衰期为1.2min。在一个更慢的过程中，这种内化蜂毒素的二聚体再次在稳定状态下产生瞬态膜开口。在摩尔基础上，合成肽类似物产生的快速过程可与蜂毒素引起的过程相媲美，但在慢相中效率更高。血红蛋白和碳酸酐酶通过开口的逸出受扩散控制。这些结果表明，蜂毒蛋白样细胞毒性肽的活性所必需的功能单元是一个由20个氨基酸组成的亲疏比大于1的两亲性α -螺旋和一个具有高浓度正电荷的短片段。
The cytotoxic peptide from honeybee venom, melittin, and a synthetic peptide analogue of it lyse human erythrocytes in a biphasic process. The kinetics of the lysis in 0.30 M sucrose, 0.01 M sodium phosphate, pH 7.30 at 4 degrees C were investigated. Our results show that melittin rapidly binds to the outer surface of the erythrocyte membrane, and the surface-bound monomers produce transient openings through which approximately 40 hemoglobin molecules can escape. Concomitantly, the melittin loses its ability to effect the process, presumably by translocation through the bilayer. The half-life for this process is 1.2min. In a much slower process, dimers of this internalized melittin again produce transient membrane openings in a steady state. On a molar basis, the synthetic peptide analogue produces a fast process comparable to that caused by melittin, but is more efficient in the slow phase. Escape of hemoglobin and of carbonic anhydrase through the openings is diffusion controlled. These results suggest that the functional units necessary for the activity of melittin-like cytotoxic peptides are a 20 amino acid amphiphilic alpha-helix with a hydrophobic:hydrophilic ratio greater than 1 and a short segment with a high concentration of positive charges.