Assessment of the functional diversity of human myoglobin

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• 作者：Matthias Totzeck¹ ; Ulrike B. Hendgen-Cotta¹ ; Christos Rammos ; Aniela M. Petrescu ; Christian Meyer ; Jan Balzer ; Malte Kelm ; Tienush Rassaf ; ^{Tienush.Rassaf@med.uni-duesseldorf.de}
• 关键词：Mb ; myoglobin ; I/R ; ischemia&ndash ; reperfusion
• 刊名：Nitric Oxide
• 出版年：2012
• 期刊代码：181_10898603
• 类别：bio
• 出版时间：15 May, 2012
• 卷：26
• 期：4
• 页码：211-216
• 文件大小：548 K

摘要

Myoglobin is presumably the most studied protein in biology. Its functional properties as a dioxygen storage and facilitator of dioxygen transport are widely acknowledged. Experimental evidence also implicates an essential role for myoglobin in the heart in regulating nitric oxide homeostasis. Under normoxia, oxygenated myoglobin can scavenge excessive nitric oxide, while under hypoxia, deoxygenated myoglobin can reduce nitrite, an oxidative product of nitric oxide, to bioactive nitric oxide. Myoglobin-driven nitrite reduction can protect the heart from ischemia and reperfusion injury. While horse and mouse myoglobin have been previously described to reduce nitrite under these conditions, a comparable activity has not been detected in human myoglobin. We here show that human myoglobin is a fully functional nitrite reductase. To study the role of human myoglobin for nitric oxide homeostasis we used repeated photometric wavelength scans and chemiluminescence based experiments. The results revealed that oxygenated human myoglobin reacts with nitrite-derived nitric oxide to form ferric myoglobin and that deoxygenated human myoglobin acts as a nitrite reductase in vitro and in situ. Rates of both nitric oxide scavenging and nitrite reduction were significantly higher in human compared to horse myoglobin. These data extend the existing knowledge about the functional properties of human myoglobin and are the basis for further translational studies towards the importance of myoglobin for nitric oxide metabolism in humans.