its discovery. Because it was discovered so recently, the function of sulfiredoxin is not yet fully known. Sulfiredoxin knockout mice is available in Dr. Qiou Wei's lab at University of Kentucky and mice are found normal under normal circumstances. On treatment of these mice with carcinogens, Srx knockout mice were found to be less prone to few cancer types compared to wildtype mice. It shows the critical role of Srx in carcinogenesis of human tumors. References Findlay, V. J., Townsend, D. M., Morris, T. E., Fraser, J. P., He, L. and Tew, K. D. (2006) A novel role for human sulfiredoxin in the reversal of glutathionylation. Cancer Res. 66, 6800-6806 Sun, Y., Hegamyer, G. and Colburn, N. H. (1994) Molecular cloning of five messenger RNAs differentially expressed in preneoplastic or neoplastic JB6 mouse epidermal cells: one is homologous to human tissue inhibitor of metalloproteinases-3. Cancer Res. 54, 1139–1144 Kwak, M. K., Wakabayashi, N., Itoh, K., Motohashi, H., Yamamoto, M. and Kensler, T. W. (2003) Modulation of gene expression by cancer chemopreventive dithiolethiones through the Keap1-Nrf2 pathway. Identification of novel gene clusters for cell survival. J. Biol. Chem. 278, 8135-8145 Wimmer, U., Wang, Y., Georgiev, O. and Schaffner, W. (2005) Two major branches of anti-cadmium defense in the mouse: MTF-1/metallothioneins and glutathione. Nucleic Acids Res 33, 5715-5727 Welch, K. D., Reilly, T. P., Bourdi, M., Hays, T., Pise-Masison, C. A., Radonovich, M. F., Brady, J. N., Dix, D. J. and Pohl, L. R. (2006) Genomic identification of potential risk factors during acetaminophen-induced liver disease in susceptible and resistant strains of mice. Chem Res Toxicol 19, 223-233 Edwards, M. G., Sarkar, D., Klopp, R., Morrow, J. D., Weindruch, R. and Prolla, T. A. (2003) Age-related impairment of the transcriptional responses to oxidative stress in the mouse heart. Physiol Genomics 13, 119-127 EC 1.8.98 Enzymes of unknown structure