Pumford N R, Martin B M, Hinson J A
Department of Pharmacology and Toxicology, University of Arkansas for Medical Sciences, Little Rock 72206.
Biochem Biophys Res Commun. 1992 Feb 14;182(3):1348-55. doi: 10.1016/0006-291x(92)91881-p.
Acetaminophen is metabolized by cytochrome P450 to a reactive metabolite that covalently binds to proteins and this binding correlates with the hepatotoxicity. The major protein adduct was previously reported to be a 55 kDa protein that was detected on Western blots using antisera specific for 3-(cystein-S-yl)acetaminophen. In this study, the 55 kDa protein was isolated using a combination of ion exchange fast flow chromatography, hydroxyapatite HPLC and anion exchange HPLC. Amino acid sequences of 8 internal peptides from a trypsin digestion of the 55 kDa protein were found to have 97% homology with the deduced amino acid sequence from a cDNA that corresponds to a 56 kDa selenium binding protein. This is the first report of a specific protein to which a metabolite of acetaminophen covalently binds.
对乙酰氨基酚通过细胞色素P450代谢为一种活性代谢产物，该代谢产物与蛋白质共价结合，这种结合与肝毒性相关。先前报道主要的蛋白质加合物是一种55 kDa的蛋白质，使用针对3-(半胱氨酸-S-基)对乙酰氨基酚的抗血清在蛋白质免疫印迹法中检测到。在本研究中，通过离子交换快速流动色谱、羟基磷灰石高效液相色谱和阴离子交换高效液相色谱相结合的方法分离出了55 kDa的蛋白质。对55 kDa蛋白质经胰蛋白酶消化得到的8个内部肽段的氨基酸序列分析发现，其与对应于56 kDa硒结合蛋白的cDNA推导的氨基酸序列具有97%的同源性。这是关于对乙酰氨基酚代谢产物共价结合的一种特异性蛋白质的首次报道。
