INFRARED STUDIES ON THE INTERACTION OF CARBON-MONOXIDE WITH DIVALENT NICKEL IN HYDROGENASE FROM CHROMATIUM-VINOSUM
INFRARED STUDIES ON THE INTERACTION OF CARBON-MONOXIDE WITH DIVALENT NICKEL IN HYDROGENASE FROM CHROMATIUM-VINOSUM
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DOI：
10.1021/bi00197a026
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发表时间：
1994-08-09
期刊：
影响因子：
2.9
通讯作者：
WOODRUFF, WH
中科院分区：
文献类型：
--
作者：
BAGLEY, KA;VANGARDEREN, CJ;WOODRUFF, WH
红外光谱的一碳一氧结合的形式的EPR沉默镍（II）物种的氢化酶分离Chromatium vinosum。这些光谱在2060 cm（-1）处显示了金属-CO络合物的nu（CO）谱带。当酶暴露于（CO）-C-13时，该吸光度变为2017 cm（-1）。该谱带归因于Ni（II）-CO物种的nu（CO）。结果表明，该物种上的CO在低温下是光不稳定的，但在200 K以上的温度下重新结合形成原始的一氧化碳物种。除了nu（CO）谱带外，还在2082、2069和1929 cm（-1）处检测到红外线，这些谱线在Ni中的CO光解后频率略有升高。这些红外带不是由CO本身产生的，因为这些带的频率不受酶暴露于（CO）-C-13的影响。在D2 O中的实验表明，这些谱带不是由可交换的氢物种产生的。它的结论是，这些非CO频带产生的物种附近或协调的Ni活性位点。这些频带的可能性质进行了讨论。
Infrared spectra of a carbon monoxy-bound form of the EPR silent Ni(II) species of hydrogenase isolated from Chromatium vinosum are presented. These spectra show a band at 2060 cm(-1) due to nu(CO) for a metal-CO complex. This absorbance shifts to 2017 cm(-1) upon exposure of the enzyme to (CO)-C-13. This band is attributed to nu(CO) from a Ni(II)-CO species. It is shown that the CO on this species is photolabile at cryogenic temperatures but rebinds to form the original carbon monoxy species at temperatures above 200 K. In addition to the nu(CO) band, infrared lines are detected at 2082, 2069, and 1929 cm(-1), which shift slightly higher in frequency upon photolysis of the CO from the Ni. These infrared bands do not arise from CO itself on the basis of the fact that the frequency of these bands is unaffected by exposure of the enzyme to (CO)-C-13. Experiments in D2O show that these bands do not arise from an exchangeable hydrogen species. It is concluded that these non-CO bands arise from species near or coordinated to the Ni active site. The possible nature of these bands is discussed.