A Novel Peptide SeCys-Gly-Pro-Cys, An Active Site Model of Thioredoxin: Synthesis and Glutathione Peroxidase-like Activity

Abstract

A tetrapeptide, Secys-Gly-Pro-Cys, is a selenium analog of the peptide moiety occuring at the active site of thioredoxin, which forms an intramolecular 14-membered disulfide loop structure in the oxidized state. We have synthesized the selenium-containing tetrapeptide, and studied its glutathione peroxidase-like activity. The tetrapeptide showed glutathione peroxidase-like activity, which was three times higher than those of glutaselenone and diphenyldiselenide. The high catalytic activity is considered to be due to the intramolecular selenosulfide bond formation in the catalysis.