嗜热四膜虫微管蛋白-秋水仙碱复合物的解离常数。

Dissociation constant of Tetrahymena tubulin-colchicine complex.

作者信息

Maekawa S

出版信息

J Biochem. 1978 Sep;84(3):641-6. doi: 10.1093/oxfordjournals.jbchem.a132169.

DOI:10.1093/oxfordjournals.jbchem.a132169

Abstract

Tetrahymena tubulin has a very low affinity for colchicine. The dissociation rate constant (k-1) and association rate constant(k+1) of Tetrahymena tubulin for colchicine were determined in comparison with those of porcine brain tubulin. The k+1 value of Tetrahymena tubulin was about one-twentieth that of porcine brain tubulin, and k-1 of Tetrahymena tubulin was about 680 times greater than that of brain tubulin. The dissociation constant (k-1/k+1) of Tetrahymena tubulin (2.7 X 10(-3) turned out to be ten thousand times greater than that of brain tubulin. This large Kd value explains well the high colchicine concentration requirement reported to block cell division of cilia regeneration of this protozoan.

摘要

嗜热四膜虫微管蛋白对秋水仙碱的亲和力非常低。与猪脑微管蛋白相比，测定了嗜热四膜虫微管蛋白与秋水仙碱的解离速率常数（k-1）和结合速率常数（k+1）。嗜热四膜虫微管蛋白的k+1值约为猪脑微管蛋白的二十分之一，而嗜热四膜虫微管蛋白的k-1约为脑微管蛋白的680倍。嗜热四膜虫微管蛋白的解离常数（k-1/k+1）（2.7×10（-3））结果比脑微管蛋白大一万倍。这个大的Kd值很好地解释了据报道阻断这种原生动物纤毛再生细胞分裂所需的高秋水仙碱浓度。