Molecular cloning of adipocyte-derived leucine aminopeptidase highly related to placental leucine aminopeptidase oxytocinase
Molecular cloning of adipocyte-derived leucine aminopeptidase highly related to placental leucine aminopeptidase oxytocinase
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DOI：
10.1093/oxfordjournals.jbchem.a022371
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发表时间：
1999-05-01
影响因子：
2.7
通讯作者：
Tsujimoto, M
中科院分区：
文献类型：
--
作者：
Hattori, A;Matsumoto, H;Tsujimoto, M
本研究克隆了一种新的人胞浆氨肽酶--脂肪细胞来源的亮氨酸氨肽酶（A-A），其编码941个氨基酸，与胎盘亮氨酸氨肽酶（P-A）/催产素酶有43%的同源性，预测的A-A含有HEX-XH（X）（18）E共有序列，虽然推导的序列在N端附近含有一个疏水区，但该酶在COS-7细胞中表达时主要定位于细胞质，北方印迹分析表明，A-binding在所有测试的组织中表达，其中一些表达至少三种形式的mRNA，这表明基因表达的调节是复杂的。当用各种合成底物测量A-actin的氨肽酶活性时，该酶显示出对亮氨酸的偏好，从而确定A-actin是一种具有限制性底物特异性的新型亮氨酸氨肽酶。A-peptide与P-peptide具有很强的同源性，这一发现可能会导致一个新的含锌氨基肽酶亚家族的定义，该亚家族属于金属肽酶的M1家族。
In the current study, we report the cloning and initial characterization of a novel human cytosolic aminopeptidase named adipocyte-derived leucine aminopeptidase (A-LAP), The sequence encodes a 941-amino acid protein with significant homology (43%) to placental leucine aminopeptidase (P-LAP)/oxytocinase, The predicted A-LAP contains the HEX-XH(X)(18)E consensus sequence, which is characteristic of the M1 family of zinc-metallopeptidases, Although the deduced sequence contains a hydrophobic region near the N-terminus, the enzyme localized mainly in cytoplasm when expressed in COS-7 cells, Northern blot analysis revealed that A-LAP was expressed in all the tissues tested, some of which expressed at least three forms of mRNA, suggesting that the regulation of the gene expression is complex, When aminopeptidase activity of A-LAP was measured with various synthetic substrates, the enzyme revealed a preference for leucine, establishing that A-LAP is a novel leucine aminopeptidase with restricted substrate specificity. The identification of A-LAP, which reveals strong homology to P-LAP, might lead to the definition of a new subfamily of zinc-containing aminopeptidases belonging to the M1 family of metallopeptidases.