Laeverin/aminopeptidase Q, a novel bestatin-sensitive leucine aminopeptidase belonging to the M1 family of aminopeptidases
Laeverin/aminopeptidase Q, a novel bestatin-sensitive leucine aminopeptidase belonging to the M1 family of aminopeptidases
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DOI：
10.1074/jbc.m702650200
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发表时间：
2007-07-13
影响因子：
4.8
通讯作者：
Tsujimoto, Masafumi
中科院分区：
文献类型：
--
作者：
Maruyama, Masato;Hattori, Akira;Tsujimoto, Masafumi
Laeverin/aminopeptidase Q （APQ）是一种细胞表面蛋白，特异表达于人胚胎源性上皮外滋养细胞，在胎盘形成过程中侵入子宫。对Laeverin/APQ的cDNA克隆发现，该序列编码一个含有990个氨基酸残基的蛋白，Laeverin/APQ含有具有M1氨基肽酶家族特征的HEXXHX18E gluzincin基序，尽管该家族的外肽酶基序GAMEN是唯一取代HAMEN序列的。在这项研究中，我们使用杆状病毒表达系统表达了重组人Laeverin/APQ，纯化到均匀性，并对其酶学性质进行了表征。结果表明，Laeverin/APQ对合成底物具有广泛的特异性，但对leu -4-甲基香马利尔-7-酰胺具有特异性。寻找天然底物，我们发现Laeverin/ APQ能够切割多种多肽的n端氨基酸，如血管紧张素III、kisspeptin-10和内啡肽C，这些多肽在胎盘中大量表达。与其他M1氨基肽酶相比，bestatin比其他已知的氨基肽酶抑制剂更有效地抑制Laeverin/ APQ的氨基肽酶活性。这些结果表明，Laeverin/ APQis是一种新型的对贝司他汀敏感的亮氨酸氨基肽酶，并提示该酶通过调节胚胎-母体界面关键肽的生物活性在人胎盘中发挥重要作用。
Laeverin/aminopeptidase Q (APQ) is a cell surface protein specifically expressed on human embryo-derived extravillous trophoblasts that invades the uterus during placentation. The cDNA cloning of Laeverin/APQ revealed that the sequence encodes a protein with 990 amino acid residues, and Laeverin/APQ contains the HEXXHX18E gluzincin motif, which is characteristic of the M1 family of aminopeptidases, although the exopeptidase motif of the family, GAMEN, is uniquely substituted for the HAMEN sequence. In this study, we expressed a recombinant human Laeverin/APQ using a baculovirus expression system, purified to homogeneity, and characterized its enzymatic properties. It was found that Laeverin/APQ had a broad substrate specificity toward synthetic substrate, although it showed a preference for Leu-4-methylcoumaryl-7-amide. Searching natural substrates, we found that Laeverin/ APQ was able to cleave the N-terminal amino acid of several peptides such as angiotensin III, kisspeptin-10, and endokinin C, which are abundantly expressed in the placenta. In contrast to the case with other M1 aminopeptidases, bestatin inhibited the aminopeptidase activity of Laeverin/ APQ much more effectively than other known aminopeptidase inhibitors. These results indicate that Laeverin/ APQis a novel bestatin-sensitive leucine aminopeptidase and suggest that the enzyme plays important roles in human placentation by regulating biological activity of key peptides at the embryo- maternal interface.