TP-5 and Thy(1, synthesized by solid phase synthesis, have the effect to restrain the formation of superoxide anion in xanthine oxidase system in vitro. The formations of lipid peroxide in several organs (such as liver, brain and thymus) of the mice treated with TP-5, TP-5(R, active fragment of Thy(1 and active fragment of Thy(1(R of 10 (g(kg(d-1 for 10 d were decreased. That means these peptides possess the capability of antioxidezation.
