Preparation and Kinetics of a Novel Glutathione Peroxidase Mimic-Selenium-modified Hyaluronic Acid

A selenium-modified hyaluronic acid (HA) compound (SeHA) was synthesized as a mimic of glutathione peroxidase (GPX). IR and NMR spectra of SeHA predict that the -CH2 OH group of the N-acetyl-D-glucosamine in HA was modified by group -SeH. There are averagely 152 -SeH groups in one SeHA molecule. The GPX activities are 103. 88, 32. 15 and 152. 71 U/μmol, respectively, when the substrates were H2O2, BuOOH and CuOOH. Ping-pong mechanism was observed in the steady-state kinetic studies of the reactive oxygen species (ROS) consuming reaction. Result of reactions of SeHA with free radical capturer 2,6-di-tert-butyl-4-methylphenol(BHT) shows that the catalysis is based on a non-free radical-mechanism and the SeHA can not be inhibited by iodoacetate, an enzyme inhibitor.