细胞内氧气运输
中文名称
通路描述
血红蛋白是含血红素的蛋白质，可可逆地结合分子氧气。人类至少含有 5 种血红蛋白：血红蛋白、肌红蛋白、细胞球蛋白、神经球蛋白和雄球蛋白（综述 Burmester 等 2014）。肌红蛋白、神经球蛋白和细胞球蛋白是胞质球蛋白，对氧气的亲和力相似（综述 Hankeln 等 2005）。雄球蛋白是一种功能尚不清楚的更远缘的球蛋白，在睾丸中表达（Hoogewijs 等 2012）。肌红蛋白主要在肌肉组织中表达（综述 Helbo 等 2013），神经球蛋白在神经元中表达，细胞球蛋白在结缔组织成纤维细胞和平滑肌细胞中表达（综述 Pesce 等 2002, Hankeln 等 2004, Ascenzi 等 2016）。与肌红蛋白不同，神经球蛋白和细胞球蛋白含有六配位血红素铁：铁原子被血红素中的 4 个氮原子和 2 个球蛋白中的半胱氨酸残基结合。其中一种半胱氨酸的结合是可逆的，这允许铁原子结合各种配体，如分子氧气、一氧化碳和二氧化氮（综述 Kakar 等 2010）。神经球蛋白可能在氧气稳态中发挥作用，但其氧气结合活性的重要性尚不清楚（综述 Pesce 等 2002, Hankeln 等 2005）。细胞球蛋白可能参与二氧化氮代谢（Thuy 等 2016, Liu 等 2017）。球蛋白还可以通过与二氧化氮（NO）的反应调节氧气稳态。氧合球蛋白通过氧化清除二氧化氮，而脱氧球蛋白可作为二氧化氮还原酶产生二氧化氮（综述 Hendgen-Cotta 等 2014, Tejero 和 Gladwin 2014）。
英文描述
Intracellular oxygen transport Globins are heme-containing proteins that reversibly bind molecular oxygen. Humans contain at least 5 types of globins: hemoglobins, myoglobin, cytoglobin, neuroglobin, and androglobin (reviewed in Burmester et al. 2014). Myoglobin, neuroglobin, and cytoglobin are cytosolic globins with similar affinities for oxygen (reviewed in Hankeln et al. 2005). Androglobin is a more distantly related globin of uncertain function that is expressed in testes (Hoogewijs et al. 2012). Myoglobin is predominantly expressed in muscle tissue (reviewed in Helbo et al. 2013), neuroglobin is expressed in neurons, and cytoglobin is expressed in connective tissue fibroblasts and smooth muscle cells (reviewed in Pesce et al. 2002, Hankeln et al. 2004, Ascenzi et al. 2016). Whereas myoglobin contains pentacoordinated heme iron, neuroglobin and cytoglobin contain hexacoordinated heme iron: the iron atom is bound by 4 nitrogen atoms of heme and 2 histidine residues of the globin. Binding by one of the histidines is reversible, which allows the iron atom to bind various ligands such as molecular oxygen, carbon monoxide, and nitric oxide (reviewed in Kakar et al. 2010). Neuroglobin may function in oxygen homeostasis, however the importance of its oxygen-binding activity is unclear (reviewed in Pesce et al. 2002, Hankeln et al. 2005). Cytoglobin may function in nitric oxide metabolism (Thuy et al. 2016, Liu et al. 2017). Globins can also regulate oxygen homeostasis via reactions with nitric oxide (NO), a vasodilator. Oxygenated globins scavenge NO by oxidation while deoxygenated globins can act as a nitrite reductase to produce NO (reviewed in Hendgen-Cotta et al. 2014, Tejero and Gladwin 2014).
所含基因
3 个基因