ARYLAMINE ACTIVATING SULFOTRANSFERASE IN LIVER

Carcinogenic N-hydroxy-arylamines and -arylamides undergo metabolic ac tivation by several enzymes in mammals to cause the DNA damage. Cytoso lic sulfotransferases in rat and human livers, which belong to the ST1 (SULT1) family, have been studied to assess their properties to media te the metabolic activation. A human orthologue of rat ST1C1 form, whi ch catalyzes sulfation of N-hydroxy-2-acetylaminofluorene, was screene d in a EMBL genomic library with ST1C1 cDNA [Nagata, K., S. Ozawa, M. Miyata, M. Shimada, D.-W. Gong, Y. Yamazoe and R. Kato (1993) J. Biol. Chem., 268, 24720-24725]. Sequencing of the hybridized clones indicat e that at least 3'-terminal region of human ST1C1 orthologue contains sequence highly homologous to rat ST1C1 at both nucleotide and deduced amino acid levels. The experiments using anti-rat ST1C1 antibody and nucleotide probes for human ST1C1 showed no detectable band in Western blots and an mRNA-detecting method with polymerase chain reaction, re spectively, in human liver samples.