COX15 transforms heme O to heme A

Heme A is the prosthetic group of cytochrome c oxidase, the terminal enzyme in the respiratory chain. It is formed by the action of cytochrome c oxidase assembly protein COX15 homolog (COX15) on heme O, coupled to the conversion of an unknown hydrogen acceptor molecule to its cognate hydrogen donor (Petruzzella et al. 1998, Antonicka et al. 2003, Rivett et al. 2021). Defects in COX15 cause of mitochondrial complex IV deficiency (MT-C4D; MIM:220110), also called cytochrome c oxidase deficiency resulting in a disorder of the mitochondrial respiratory chain seen as heterogeneous clinical manifestations, ranging from isolated myopathy to severe multisystem disease affecting several tissues and organs (Antonicka et al. 2003). Defects in COX15 also cause Leigh syndrome (LS; MIM:256000), an early-onset progressive neurodegenerative disorder characterised by the presence of focal, bilateral lesions in one or more areas of the central nervous system (Oquendo et al. 2004, Bugiani et al. 2005).

血红素A是细胞色素c氧化酶的辅基，呼吸链中的终末酶。其形成过程涉及细胞色素c氧化酶组装蛋白COX15同源物（COX15）对血红素O的作用，并伴随未知氢受体分子向其相应的氢供体分子的转化（Petruzzella等，1998年，Antonicka等，2003年，Rivett等，2021年）。COX15基因的缺陷是导致线粒体复合体IV缺乏症（MT-C4D；MIM：220110），亦称细胞色素c氧化酶缺乏症，表现为异质性的临床征象，从孤立性肌病到严重影响多个组织和器官的严重多系统疾病（Antonicka等，2003年）。COX15基因的缺陷还导致Leigh综合征（LS；MIM：256000），一种早发型进行性神经退行性疾病，以中枢神经系统一个或多个区域的局灶性、双侧性病变为特征（Oquendo等，2004年，Bugiani等，2005年）。