Discovery and Characterization of a Second Mammalian Thiol Dioxygenase, Cysteamine Dioxygenase
作者:John E. Dominy、Chad R. Simmons、Lawrence L. Hirschberger、Jesse Hwang、Relicardo M. Coloso、Martha H. Stipanuk
DOI:10.1074/jbc.m703089200
日期:2007.8
two known thiol dioxygenase activities in mammals, and they are ascribed to the enzymes cysteine dioxygenase (CDO) and cysteamine (2-aminoethanethiol) dioxygenase (ADO). Although many studies have been dedicated to CDO, resulting in the identification of its gene and even characterization of the tertiary structure of the protein, relatively little is known about cysteamine dioxygenase. The failure to
在哺乳动物中只有两种已知的硫醇双加氧酶活性,它们归因于半胱氨酸双加氧酶(CDO)和半胱胺(2-氨基乙硫醇)双加氧酶(ADO)。尽管已经对CDO进行了许多研究,从而确定了CDO的基因,甚至表征了蛋白质的三级结构,但对半胱胺双加氧酶的了解相对较少。未能鉴定出该蛋白质的基因,大大阻碍了我们对半胱胺代谢的理解,半胱胺是辅酶A组成型降解的产物,而牛磺酸的合成是半胱胺氧化的最终产物,并且是第二个氨基酸含量最高的氨基酸。哺乳动物组织。在这项研究中,我们鉴定了由基因Gm237编码并属于DUF1637蛋白家族的CDO(以下称为ADO)的假想鼠蛋白同源物。当表达为重组蛋白时,ADO在体外表现出显着的半胱胺双加氧酶活性。该反应对半胱胺具有高度特异性。半胱氨酸不会被该酶氧化,与结构相关的化合物也不是该反应的竞争性抑制剂。当在HepG2 / C3A细胞中过度表达时,ADO会增加半胱胺产生的次牛磺酸。同样,当人介导的