四膜虫钙结合蛋白确实是一种钙调蛋白。

Tetrahymena calcium-binding protein is indeed a calmodulin.

作者信息

Suzuki Y, Nagao S, Abe K, Hirabayashi T, Watanabe Y

出版信息

J Biochem. 1981 Jan;89(1):333-6. doi: 10.1093/oxfordjournals.jbchem.a133200.

DOI:10.1093/oxfordjournals.jbchem.a133200

Abstract

We previously isolated a Ca2+-binding protein from a ciliate, Tetrahymena, and designated it as TCBP (Tetrahymena Ca2+-binding protein). The present paper reports that TCBP, which has two high affinity Ca2+-binding sites (Kd=4.6 X 10(-6) M), could activate porcine brain cyclic nucleotide phosphodiesterase at a concentration of over 10(-6) M free Ca2+, with the same mode of activation as that of authentic (porcine brain) calmodulin. In addition, the amino acid composition of TCBP was essentially the same as that of brain calmodulin. Therefore, we conclude that TCBP as an activator of Tetrahymena guanylate cyclase is indeed a calmodulin.

摘要

我们之前从一种纤毛虫——四膜虫中分离出一种钙结合蛋白，并将其命名为TCBP（四膜虫钙结合蛋白）。本文报道，TCBP具有两个高亲和力钙结合位点（解离常数Kd = 4.6×10⁻⁶ M），在游离钙离子浓度超过10⁻⁶ M时能够激活猪脑环核苷酸磷酸二酯酶，其激活模式与天然（猪脑）钙调蛋白相同。此外，TCBP的氨基酸组成与脑钙调蛋白基本相同。因此，我们得出结论，作为四膜虫鸟苷酸环化酶激活剂的TCBP确实是一种钙调蛋白。