Dissociation of nitric oxide from soluble guanylate cyclase
Dissociation of nitric oxide from soluble guanylate cyclase
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DOI：
10.1006/bbrc.1997.7470
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发表时间：
1997-10-09
影响因子：
3.1
通讯作者：
Koesling, D
中科院分区：
文献类型：
--
作者：
Kharitonov, VG;Russwurm, M;Koesling, D
可溶性鸟苷环化酶与一氧化氮络合的动力学研究证明，在底物GTP和Mg2+存在下，NO的解离速度比没有底物时快50倍。在这两种试剂存在下，20℃时的离解速率常数为k(OBS)=0.04+/-0.01 S(-1)，这是迄今报道的亚铁血红素蛋白最快的无离解速率常数。推算到37摄氏度，这相当于在生理条件下不从可溶性鸟苷环化酶解离的半衰期约为5 S，这可能足以解释生物系统中该酶的失活。在其他各种试剂条件下，也有离解速率常数的报道。(C)1997年学术出版社。
Kinetic studies of soluble guanylate cyclase complexed with nitric oxide prove that NO dissociation in the presence of the substrate GTP and Mg2+ is as much as 50 times faster than in their absence. In the presence of those two reagents the dissociation rate constant is k(obs) = 0.04 +/- 0.01 s(-1) at 20 degrees C, which is by far the fastest NO dissociation rate constant ever reported for a ferrous heme protein. Extrapolated to 37 degrees C, this corresponds to a half life of about 5 s for NO dissociation from soluble guanylate cyclase at physiological conditions, which is presumably fast enough to account for deactivation of the enzyme in biological systems. Dissociation rate constants are also reported for a variety of other reagent conditions. (C) 1997 Academic Press.