期刊
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
卷 126, 期 38, 页码 12162-12172出版社
AMER CHEMICAL SOC
DOI: 10.1021/ja046548d
关键词
-
We have used protein film voltammetry to study the NiFe hydrogenase from Desulfovibrio fructosovorans. We show how measurements of transient activity following the addition in the electrochemical cell of H-2, CO, or O-2 allow simple and virtually instantaneous determinations of the Michaelis constant, inhibition constant, or rate of inactivation, respectively, thus opening new opportunities to study the active site of NiFe hydrogenases. The binding and release of CO occur within a fraction of a second, and we determine and discuss how its affinity for the active site changes as the driving force for the H+/H-2 reaction is continuously varied. Inactivation by O-2 is a slow, bimolecular process (with pH-independent rate constant 3 x 10(4) s(-1) M-1 at 40 degreesC, under one atm of H-2) that leads to a mixture of fully oxidized states, and unlike the case of CO inhibition, the active site is not fully protected by H-2. This experimental approach could be used to study the reaction of other multicentered metalloenzymes with their gaseous substrates or inhibitors.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据