Identification of carboxypeptidase N as an enzyme responsible for C-terminal cleavage of stromal cell-derived factor-1α in the circulation
Identification of carboxypeptidase N as an enzyme responsible for C-terminal cleavage of stromal cell-derived factor-1α in the circulation
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DOI：
10.1182/blood-2004-12-4618
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发表时间：
2005-06-15
期刊：
影响因子：
20.3
通讯作者：
Tosato, G
中科院分区：
文献类型：
--
作者：
Davis, DA;Singer, KE;Tosato, G
趋化因子基质衍生因子 1 α (SDF-1 α) 是造血、淋巴细胞归巢、前 B 细胞生长和血管生成的重要调节因子。由于 SDF-1 α 在许多组织中组成型表达，趋化因子功能主要通过蛋白水解降解来调节。人血清在两个末端裂解 68 个氨基酸的趋化因子 SDF-1 α。尚未确定负责从 SDF-1 α 中去除羧基末端赖氨酸并导致生物活性显着降低的酶。使用一种新的生化测定法来测量羧基末端裂解活性，我们从血清和血浆中纯化了一种肽酶，该肽酶可以特异性去除 SDF-1 α 中的羧基末端赖氨酸，并将其鉴定为羧肽酶 N（CPN，也称为激肽酶 1、精氨酸羧肽酶和过敏毒素灭活剂）。我们证明血清和血浆中的 SDF-1 α 缺乏羧基末端赖氨酸，并且血清和血浆中 CPN 的消耗显着降低了 SDF-1 α 羧肽酶活性。纯化的 CPN 有效且特异性地去除 SDF-1 α 的羧基末端赖氨酸，并显着降低趋化因子作为前 B 细胞生长因子和趋化剂的生物活性。因此，除了作为激肽和过敏毒素生物活性调节剂的作用外，CPN 通过降低趋化因子特异性活性，也是 SDF-1 α 生物活性的重要调节剂。 (c) 2005 年，美国血液学会。
The chemokine stromal-derived factor-1 alpha (SDF-1 alpha) is an essential regulator of hematopoiesis, lymphocyte homing, pre-B-cell growth, and angiogenesis. As SDF-1 alpha is constitutively expressed in many tissues, chemokine function is mostly regulated by proteolytic degradation. Human serum cleaves the 68-amino acid chemokine, SDF-1 alpha, at both termini. The enzyme or enzymes responsible for the removal of the carboxy-terminal lysine from SDF-1 alpha, leading to significant reduction in biologic activity, have not been identified. Using a new biochemical assay for measuring the carboxy-terminal cleavage activity, we purified from serum and plasma a peptidase that specifically removes the carboxy-terminal lysine from SDF-1 alpha and identified it as carboxypeptidase N (CPN, also known as kininase 1, arginine carboxypeptidase, and anaphylotoxin inactivator). We demonstrate that SDF-1 alpha in serum and plasma lacks the carboxy terminal lysine, and depletion of CPN from serum and plasma significantly reduces the SDF-1 alpha carboxylpeptidase activity. Purified CPN effectively and specifically removes the carboxy-terminal lysine from SDF-1 alpha and significantly reduces the chemokine's biologic activity as a pre-B-cell growth factor and chemoattractant. Thus, in addition to its role as a regulator of the biologic activity of kinins and anaphylatoxins, CPN is an important regulator of the biologic activity of SDF-1 alpha, by reducing the chemokine-specific activity. (c) 2005 by The American Society of Hematology.