The mechanism of action of vinblastine. Binding of [acetyl-3H]vinblastine to embryonic chick brain tubulin and tubulin from sea urchin sperm tail outer doublet microtubules.
The mechanism of action of vinblastine. Binding of [acetyl-3H]vinblastine to embryonic chick brain tubulin and tubulin from sea urchin sperm tail outer doublet microtubules.
复制标题
长春花碱的作用机制。
DOI：
10.1021/bi00697a008
复制
发表时间：
1975
期刊：
影响因子：
2.9
通讯作者：
D. Chin
中科院分区：
文献类型：
--
作者：
L. Wilson;K. Creswell;D. Chin
氚标记的长春碱，比活度107 Ci/mol，通过去乙酰长春碱与[3 H]乙酸酐的乙酰化反应制备，并已用于研究长春碱与微管蛋白的结合。每摩尔鸡胚脑微管蛋白有两个高亲和力的长春碱结合位点（KA = 3-5 × 10（5）l./mol）。mol）。这些位点的结合是迅速的，并且在37 - 0 ℃之间相对独立于温度。硫酸长春碱和硫酸脱乙酰长春碱，两个其他活性长春花生物碱衍生物，竞争性抑制长春碱的结合。长春新碱的抑制常数为1.7 × 10（-5）M;去乙酰长春碱的抑制常数为2 × 10（-5）M。微管蛋白的长春碱结合活性随老化而衰减，但未详细研究此性质。长春碱不能降解海胆精子尾部的外双联体微管，也不能与这些微管结合。而从微管外偶联体的B亚纤维中溶解的微管蛋白具有两个高亲和力结合位点（KA = 1-3 × 105 l./摩尔）。这些数据表明，长春碱主要通过抑制微管聚合来破坏细胞中的微管，而不直接破坏预先形成的微管。
Tritium-labeled viblastine, specific activity 107 Ci/mol, was prepared by acetylation of desacetylvinblastine with [3H]acetic anhydride, and has been employed in a study of vinblastine binding to tubulin. There are two high affinity vinblastine-binding sites per mole of embryonic chick brain tubulin (KA = 3-5 X 10(5) l./mol). Binding to these sites was rapid, and relatively independent of temperature between 37 and 0degreeC. Vincristin sulfate and desacetylvinblastine sulfate, two other active vinca alkaloid derivatives, competitively inhibited the binding of vinblastine. The inhibition constant for vincristine was 1.7 X 10(-5) M; and for desacetylvinblastine, 2 X 10(-5) M. The vinblastine binding activity of tubulin decayed upon aging, but this property was not studied in detail. Vinblastine did not depolymerize stable sea urchin sperm tail outer doublet microtubules, nor did it bind to these microtubules. However, tubulin solubilized from the B subfiber of the outer doublet microtubules possessed the two high affinity binding sites (KA = 1-3 X 105 l./mol). These data suggest that vinblastine destroys microtubules in cells primarily by inhibition of microtubule polymerization, and does not directly destroy preformed microtubules.