Bioimprinted protein exhibits glutathione peroxidase activity

A strategy for design of bioimprinted proteins with glutathione peroxidase (GPX) activity has been proposed. The proteins imprinted with a glutathione derivative were converted into selenium-containing proteins by chemical modifying the reactive hydroxyl groups of serines followed by sodium hydrogen selenide displacement. These selenium-containing proteins exhibited remarkable GPX activities and the GPX activities of reduction of H2O2 by glutathione (GSH) were found to be 101– 817 U (mu)mol^-1, which approaches the activity of a selenium-containing catalytic antibody elicited by a hapten similar to our template. The steady state kinetic study for imprinted protein catalysis revealed Michaelis–Menten kinetics for both H2O2 and GSH, e.g. the pesudo-first-order rate constant kcat (H2O2) and the apparent Michaelis constant Km (H2O2) at 1 mM GSH were calculated to be 784 min^-1 and 1.24×10^-3 M, respectively, and the apparent second-order rate constant kcat (H2O2)/Km (H2O2) was determined to be 6.33×10^5 (M min)^-1. The kinetics and the template inhibition showed that the strategy might be a remarkably efficient one for generating artificial enzyme with GPX activity.