Abstract: On the basis of the framework of hyaluronic acid(HA), two novel modified hyaluronic acid compounds, named as SeHA and TeHA, were synthesized to be functioned as mimics of glutathione peroxidase(GPX) by using the method of chemical modification. The structures of the two mimics were characterized by means of IR and NMR with the conclusion that the target —SeH and —TeH were located at —CH₂OH of the N-acetyl-D-glucosamine. After the new compound was prepared and purified, DTNB method was used to determine the selenium content in SeHA to be 1.2%. The GPX activities of the mimics with H₂O₂, tert-butyl hydroperoxide(t-BuOOH) and cumenyl hydroperoxide(CuOOH) as the substrates were measured, the result of which illustrates that CuOOH is the optimal substance of the mimics. In the steady-state kinetic studies, a ping-pong mechanism was observed from the data of the double reciprocal plots. All the results show that the mimics behaved similar to the native GPX. BHT and iodoacetate were applied to investigate the catalyzing mechanism of the mimic respectively. It is shown that the catalyzed mechanism is free radical and the mimic cannot be inhibited by iodoacetate.

Key words: Hyaluronic acid, Glutathione peroxidase(GPX), Mimic enzyme, Preparation, Property