THE HEMOREGULATORY PEPTIDE N-ACETYL-SER-ASP-LYS-PRO IS A NATURAL AND SPECIFIC SUBSTRATE OF THE N-TERMINAL ACTIVE-SITE OF HUMAN ANGIOTENSIN-CONVERTING ENZYME
THE HEMOREGULATORY PEPTIDE N-ACETYL-SER-ASP-LYS-PRO IS A NATURAL AND SPECIFIC SUBSTRATE OF THE N-TERMINAL ACTIVE-SITE OF HUMAN ANGIOTENSIN-CONVERTING ENZYME
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DOI：
10.1074/jbc.270.8.3656
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发表时间：
1995-02-24
影响因子：
4.8
通讯作者：
CORVOL, P
中科院分区：
文献类型：
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作者：
ROUSSEAU, A;MICHAUD, A;CORVOL, P
血管紧张素转换酶(ACE)是一种锌二肽羧肽酶，它含有两个相似的结构域，每个结构域都有一个功能活性部位。利用野生型重组ACE和两个含有单一功能位点的全长突变体，研究了每个活性部位分别参与造血干细胞增殖负调控因子循环肽AcSDKP的降解。然而，ACE的N-和C-活性部位对AcSDKP具有二肽活性，K-m值分别为31和39mUN-活性中心比C-活性中心快50倍，k(CAT)/K-m值分别为0.5和0.01µM(-1)·s(-1)。针对N-活性中心的单抗抑制了AcSDKP的水解，证实了N-活性中心在AcSDKP水解中的主导作用。AcSDKP的N-结构域特异性将有助于识别该结构域的特异性抑制剂。这是首次报道了血管紧张素转换酶N-活性部位的高度特异性底物，其动力学常数在生理底物范围内，提示血管紧张素转换酶可能通过其N-末端活性部位参与体内调节这种血液调节多肽的局部浓度。
Angiotensin I-converting enzyme (ACE) is a zinc-dipeptidyl carboxypeptidase, which contains two similar domains, each possessing a functional active site, Respective involvement of each active site in the degradation of the circulating peptide N-acetyl-seryl-aspartyl-lysyl-proline (AcSDKP), a negative regulator of hematopoietic stem cell proliferation, was studied by using wild-type recombinant ACE and two full-length mutants containing a single functional site, Both the N- and C-active sites of ACE exhibit dipeptidyl activity toward AcSDKP, with K-m values of 31 and 39 mu M, respectively, However, the N-active site hydrolyzes the peptide 50 times faster compared with the C-active site, with k(cat)/K-m values of 0.5 and 0.01 mu M(-1).s(-1), respectively, The predominant role of the N-active site in AcSDKP hydrolysis was confirmed by the inhibition of hydrolysis using a monoclonal antibody specifically directed against the N-active site, The N-domain specificity for AcSDKP will aid the identification of specific inhibitors for this domain. This is the first report of a highly specific substrate for the N-active site of ACE, with kinetic constants in the range of physiological substrates, suggesting that ACE might be involved via its N-terminal active site in the in vivo regulation of the local concentration of this hemoregulatory peptide.