Ikeo K, Takahashi K, Gojobori T
DNA Research Center, National Institute of Genetics, Mishima, Japan.
FEBS Lett. 1991 Aug 5;287(1-2):146-8. doi: 10.1016/0014-5793(91)80036-3.
Human apolipoprotein(a) has a great size heterogeneity and consists of 38 kringle domains in the amino terminal and a serine protease domain in the carboxyl terminal. All but one kringle of apolipoprotein(a) are homologous to the fourth kringle of plasminogen. However, the 38th kringle resembles the fifth kringle of plasminogen and its seems to have been deleted in simian species. The phylogenetic trees suggest that an ancestral apolipoprotein(a) may have started with a duplicate of a plasminogen type protein. It also implies that deletion of the three kringles in the amino terminus followed, and that one of the remaining two kringles was duplicated in both human and simian species and the other was processed by a deletion in simian species after species separation. Thus, the number of kringles in other mammals not yet studied may vary considerably from species to species.
人载脂蛋白(a)具有高度的大小异质性，其氨基末端由38个kringle结构域组成，羧基末端有一个丝氨酸蛋白酶结构域。载脂蛋白(a)除一个kringle结构域外，其余均与纤溶酶原的第四个kringle结构域同源。然而，第38个kringle结构域类似于纤溶酶原的第五个kringle结构域，并且在猿类物种中似乎已缺失。系统发育树表明，一个祖先载脂蛋白(a)可能起始于纤溶酶原类型蛋白的一个复制体。这也意味着随后氨基末端的三个kringle结构域发生了缺失，并且在人类和猿类物种中，剩余的两个kringle结构域之一发生了复制，另一个在物种分化后在猿类物种中因缺失而发生了加工处理。因此，尚未研究的其他哺乳动物中kringle结构域的数量可能因物种而异。
