Reactions of ferrous neuroglobin and cytoglobin with nitrite under anaerobic conditions
Reactions of ferrous neuroglobin and cytoglobin with nitrite under anaerobic conditions
复制标题
DOI：
10.1016/j.jinorgbio.2008.05.008
复制
发表时间：
2008-09-01
影响因子：
3.9
通讯作者：
Fago, Angela
中科院分区：
文献类型：
--
作者：
Petersen, Morten Gjerning;Dewilde, Sylvia;Fago, Angela
最近的证据表明，亚硝酸盐与脱氧血红蛋白和肌红蛋白的反应有助于在低氧可用性的条件下在体内产生一氧化氮和S-亚硝基硫醇。我们已经调查了是否亚铁神经珠蛋白和细胞珠蛋白，两个六配位球蛋白从脊椎动物表达在大脑和各种组织中，分别，也与亚硝酸盐在厌氧条件下反应。使用吸收光谱，我们发现，亚铁神经红蛋白和亚硝酸盐反应的二阶速率常数类似的肌红蛋白，而亚铁血红素的细胞珠蛋白不与亚硝酸盐反应。吸收光谱的解卷积表明，在神经红蛋白与亚硝酸盐的反应过程中，由于亚铁神经红蛋白对一氧化氮的低亲和力，铁Fe（III）血红素在过量的亚硝酰Fe（II）-NO血红素中产生。通过使用亚铁肌红蛋白作为一氧化氮的清除剂，我们发现一氧化氮从亚铁神经红蛋白中解离的速度比以前认识到的要快得多，与反应过程中Fe（II）-NO产物的衰变一致。当与亚硝酸盐反应时，脑红蛋白和细胞红蛋白都被S-亚硝化，其中脑红蛋白显示出更高水平的S-亚硝化。讨论了脑缺氧条件下亚硝酸盐与脑红蛋白反应的生物学意义。(C)2008年爱思唯尔公司All rights reserved.
Recent evidence suggests that the reaction of nitrite with deoxygenated hemoglobin and myoglobin contributes to the generation of nitric oxide and S-nitrosothiols in vivo under conditions of low oxygen availability. We have investigated whether ferrous neuroglobin and cytoglobin, the two hexacoordinate globins from vertebrates expressed in brain and in a variety of tissues, respectively, also react with nitrite under anaerobic conditions. Using absorption spectroscopy, we find that ferrous neuroglobin and nitrite react with a second-order rate constant similar to that of myoglobin, whereas the ferrous heme of cytoglobin does not react with nitrite. Deconvolution of absorbance spectra shows that, in the course of the reaction of neuroglobin with nitrite, ferric Fe(Ill) heme is generated in excess of nitrosyl Fe(II)-NO heme as due to the low affinity of ferrous neuroglobin for nitric oxide. By using ferrous myoglobin as scavenger for nitric oxide, we find that nitric oxide dissociates from ferrous neuroglobin much faster than previously appreciated, consistently with the decay of the Fe(II)-NO product during the reaction. Both neuroglobin and cytoglobin are S-nitrosated when reacting with nitrite, with neuroglobin showing higher levels of S-nitrosation. The possible biological significance of the reaction between nitrite and neuroglobin in vivo under brain hypoxia is discussed. (C) 2008 Elsevier Inc. All rights reserved.