Schwabe C, Büllesbach E E, Heyn H, Yoshioka M
Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston 29425.
J Biol Chem. 1989 Jan 15;264(2):940-3.
The tendency toward extremely high variability among relaxins derived from purportedly closely related species has come to an abrupt end with the discovery of quasi-porcine relaxin in the minke whale (Balaenoptera acutorostrata) and the Bryde's whale (Balaenoptera edeni). An aqueous abstract of the corpora lutea of the two baleen whales contained significant amounts of relaxin-like activity as determined by a mouse bioassay and by cross-reactivity with anti-pig relaxin antibodies. The activity could be isolated and purified to homogeneity. Sequence analysis revealed that both whale relaxins differed from each other by about 3 residues, whereas the relaxin of B. edeni differed at only one position from that of pig relaxin. The similarity appears to include even the chain length heterogeneity observed at the C-terminal end of the B chain in porcine relaxin which is produced by a peculiar mode of connecting peptide removal from the pro-hormone. This finding may well represent one of the better documented challenges to the current paradigm of molecular evolution.
在小须鲸（Balaenoptera acutorostrata）和布氏鲸（Balaenoptera edeni）中发现准猪松弛素后，源自据称亲缘关系密切物种的松弛素之间极高变异性的趋势戛然而止。通过小鼠生物测定法以及与抗猪松弛素抗体的交叉反应性测定，这两种须鲸的黄体水提取物含有大量松弛素样活性。该活性可以被分离并纯化至同质。序列分析表明，两种鲸松弛素彼此之间相差约3个残基，而布氏鲸的松弛素与猪松弛素仅在一个位置上不同。这种相似性甚至似乎包括在猪松弛素B链C末端观察到的链长异质性，这种异质性是由从激素原中去除连接肽的特殊方式产生的。这一发现很可能是对当前分子进化范式记载较为充分的挑战之一。
