Sakakibara Y, Yanagisawa K, Katafuchi J, Ringer D P, Takami Y, Nakayama T, Suiko M, Liu M C
Department of Biochemistry, University of Texas Health Center, Tyler, Texas 75710, USA.
J Biol Chem. 1998 Dec 18;273(51):33929-35. doi: 10.1074/jbc.273.51.33929.
Upon sulfonation, carcinogenic hydroxyarylamines such as N-hydroxy-2-acetylaminofluorene (N-OH-2AAF) can be further activated to form ultimate carcinogens in vivo. Previous studies have shown that a SULT1C1 sulfotransferase is primarily responsible for the sulfonation of N-OH-2AAF in rat liver. In the present study, two novel human sulfotransferases shown to be members of the SULT1C sulfotransferase subfamily based on sequence analysis have been cloned, expressed, and characterized. Comparisons of the deduced amino acid sequence encoded by the human SULT1C sulfotransferase cDNA 1 reveal 63.7, 61.6, and 85.1% identity to the amino acid sequences of rat SULT1C1 sulfotransferase, mouse SULT1C1 sulfotransferase, and rabbit SULT1C sulfotransferase. In contrast, the deduced amino acid sequence of the human SULT1C sulfotransferase 2 cDNA displays 62.9, 63.1, 63.1, and 62.5% identity to the amino acid sequences of the human SULT1C sulfotransferase 1, rat SULT1C1 sulfotransferase, mouse SULT1C1 sulfotransferase, and rabbit SULT1C sulfotransferase. Recombinant human SULT1C sulfotransferases 1 and 2, expressed in Escherichia coli and purified to near electrophoretic homogeneity, were shown to cross-react with the antiserum against the rat liver SULT1C1 sulfotransferase and exhibited sulfonating activities with N-OH-2AAF as substrate. Tissue-specific expression of these novel human SULT1C sulfotransferases were examined by employing the Northern blotting technique. The results provide a foundation for the investigation into the functional relevance of these new SULT1C sulfotransferases in different human tissues/organs.
在磺化过程中，致癌性羟基芳胺如N - 羟基 - 2 - 乙酰氨基芴（N - OH - 2AAF）可在体内进一步活化形成最终致癌物。先前的研究表明，SULT1C1磺基转移酶主要负责大鼠肝脏中N - OH - 2AAF的磺化。在本研究中，基于序列分析显示为SULT1C磺基转移酶亚家族成员的两种新型人类磺基转移酶已被克隆、表达和表征。由人类SULT1C磺基转移酶cDNA 1编码的推导氨基酸序列与大鼠SULT1C1磺基转移酶、小鼠SULT1C1磺基转移酶和兔SULT1C磺基转移酶的氨基酸序列相比，同一性分别为63.7%、61.6%和85.1%。相比之下，人类SULT1C磺基转移酶2 cDNA的推导氨基酸序列与人类SULT1C磺基转移酶1、大鼠SULT1C1磺基转移酶、小鼠SULT1C1磺基转移酶和兔SULT1C磺基转移酶的氨基酸序列相比，同一性分别为62.9%、63.1%、63.1%和62.5%。在大肠杆菌中表达并纯化至接近电泳纯的重组人类SULT1C磺基转移酶1和2，显示与抗大鼠肝脏SULT1C1磺基转移酶的抗血清发生交叉反应，并以N - OH - 2AAF为底物表现出磺化活性。通过Northern印迹技术检测了这些新型人类SULT1C磺基转移酶的组织特异性表达。这些结果为研究这些新的SULT1C磺基转移酶在不同人类组织/器官中的功能相关性奠定了基础。
