1400W is a slow, tight binding, and highly selective inhibitor of inducible nitric-oxide synthase in vitro and in vivo
1400W is a slow, tight binding, and highly selective inhibitor of inducible nitric-oxide synthase in vitro and in vivo
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DOI：
10.1074/jbc.272.8.4959
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发表时间：
1997-02-21
影响因子：
4.8
通讯作者：
Knowles, RG
中科院分区：
文献类型：
--
作者：
Garvey, EP;Oplinger, JA;Knowles, RG
N-（3-（氨甲基）苄基）乙脒（1400 W）是一种缓慢的、紧密结合的人诱导型一氧化氮合酶（iNOS）抑制剂，1400 W的缓慢抑制作用呈饱和动力学，最大速率常数为0.028s（-1），结合常数为2.0 μ M。抑制作用依赖于辅因子NADPH。L-精氨酸是1400 W结合的竞争性抑制剂，其K_s值为3.0 μ M。因此，1400 W是人iNOS的不可逆抑制剂或极其缓慢的可逆抑制剂，其Kd值小于或等于7 nM。相反，对人神经元NOS和内皮NOS（eNOS）的抑制相对较弱，快速可逆，并且与L-精氨酸竞争，Ri值分别为2 μ M和50 μ M。因此，1400 W对MOS的选择性至少是eNOS的5000倍。这种选择性与在大鼠主动脉环中观察到的相似，其中1400 W对大鼠iNOS的效力比eNOS高1000倍以上。最后，在大鼠内毒素诱导的血管损伤模型中，1400 W对iNOS的作用比eNOS强50倍以上。因此，1400 W在体外和体内抑制iNOS的效力和选择性远远大于任何先前描述的iNOS抑制剂。
N-(3-(Aminomethyl)benzyl)acetamidine (1400W) was a slow, tight binding inhibitor of human inducible nitric-oxide synthase (iNOS), The slow onset of inhibition by 1400W showed saturation kinetics with a maximal rate constant of 0.028 s(-1) and a binding constant of 2.0 mu M. Inhibition was dependent on the cofactor NADPH. L-Arginine was a competitive inhibitor of 1400W binding with a K-s value of 3.0 mu M Inhibited enzyme did not recover activity after 2 h. Thus, 1400W was either an irreversible inhibitor or an extremely slowly reversible inhibitor of human iNOS with a K-d value less than or equal to 7 nM. In contrast, inhibition of human neuronal NOS and endothelial NOS (eNOS) was relatively weaker, rapidly reversible, and competitive with L-arginine, with Ri values of 2 mu M and 50 mu M, respectively, Thus, 1400W was at least 5000-fold selective for MOS versus eNOS. This selectivity was similar to that observed in rat aortic rings, in which 1400W was greater than 1000-fold more potent against rat iNOS than eNOS. Finally, 1400W was greater than 50-fold more potent against iNOS than eNOS in a rat model of endotoxin-induced vascular injury. Thus, the potency and selectivity of 1400W inhibition of iNOS both in vitro and in vivo were far greater than of any previously described iNOS inhibitor.