Tomkinson B
Department of Veterinary Medical Chemistry, Swedish University of Agricultural Sciences, Uppsala.
Biochem J. 1994 Dec 1;304 ( Pt 2)(Pt 2):517-23. doi: 10.1042/bj3040517.
Tripeptidyl-peptidase II (TPP II) is a cytosolic high-M(r) exopeptidase with an active site of the subtilisin type. This paper describes cloning of cDNA encoding murine TPP II. Four clones were isolated from a murine mastocytoma cDNA library and the 5'-end was isolated by use of 5'-RACE (rapid amplification of cDNA ends). A total of 4611 bp were isolated, including the complete coding region. The deduced amino acid sequence shows a 96% overall identity when compared with the previously cloned human TPP II. The remarkably high identity indicates that not only the catalytic domain, but almost the entire subunit, must be of functional importance. Alignment with subtilisin-like serine peptidases identified Asp44, His264 and Ser449 as the catalytic triad, thus defining an extra domain of approximately 200 amino acids between the catalytic Asp and His in TPP II as compared with other subtilases. In addition, it was demonstrated that different polyadenylation signals can be utilized, since two different clones with untranslated 3'-ends of 155 bp and 781 bp respectively have been isolated. Finally, one of the isolated clones contains an extra 39 bp insert encoding 13 amino acids, which implies alternative splicing of the mRNA.
三肽基肽酶II（TPP II）是一种胞质高分子量外肽酶，具有枯草杆菌蛋白酶型活性位点。本文描述了编码小鼠TPP II的cDNA的克隆。从鼠肥大细胞瘤cDNA文库中分离出四个克隆，并通过5'-RACE（cDNA末端快速扩增）分离出5'-末端。总共分离出4611 bp，包括完整的编码区。与先前克隆的人TPP II相比，推导的氨基酸序列显示出96%的总体同一性。这种非常高的同一性表明，不仅催化结构域，而且几乎整个亚基都必须具有功能重要性。与枯草杆菌蛋白酶样丝氨酸肽酶的比对确定Asp44、His264和Ser449为催化三联体，因此与其他枯草杆菌蛋白酶相比，在TPP II的催化Asp和His之间定义了一个约200个氨基酸的额外结构域。此外，已证明可以利用不同的聚腺苷酸化信号，因为分别分离出了两个具有155 bp和781 bp的非翻译3'-末端的不同克隆。最后，分离出的一个克隆包含一个额外的39 bp插入片段，编码13个氨基酸，这意味着mRNA存在可变剪接。
