ABSTRACT
Superoxide dismutase (SOD), glutathione peroxidase (GPX) and catalase (CAT) play crucial roles in balancing the production and decomposition of reactive oxygen species (ROS) in living organisms. These enzymes act cooperatively and synergistically to scavenge ROS. In order to imitate the synergism of these enzymes, we designed and synthesized a novel 32-mer peptide (32P) on the basis of the previous 15-mer peptide with GPX activity and a 17-mer peptide with SOD activity. Upon the selenation and chelation of copper, the 32-mer peptide is converted to a new Se- and Cu-containing 32-mer peptide (Se-Cu-32P) and displays both SOD and GPX activities and its kinetics was studied. Moreover, the novel peptide was demonstrated to be able to better protect vero cells from the injury induced by xanthine oxidase (XOD)/xanthine/Fe2+ damage system than its parents. Thus, this bifunctional enzyme imitated the synergism of SOD and GPX and could be a better candidate of therapeutic medicine.
Subject(s)
Glutathione Peroxidase/chemistry , Peptides/chemistry , Superoxide Dismutase/chemistry , Animals , Chlorocebus aethiops , Copper/chemistry , Glutathione Peroxidase/chemical synthesis , Glutathione Peroxidase/pharmacology , Kinetics , Oxidative Stress/drug effects , Peptides/chemical synthesis , Peptides/pharmacology , Selenium/chemistry , Superoxide Dismutase/chemical synthesis , Superoxide Dismutase/pharmacology , Vero CellsABSTRACT
The emission spectra of SrAl12O19 : Pr3+ at temperature from 308 to 483 K were investigated under vacuum ultraviolet excitation. Both the dipole-forbidden 4f2 --> 4f2 transition and the dipole-allowed 4f5d --> 4f2 transitions were observed. The intensity of the 4f5d --> 4f2 emission relative to that of the 4f2 --> 4f2 emission increased with increasing temperature. A thermal equilibrium model was applied to the system consisting of the 1S0 state and the lowest 4f5d states of Pr3+, and the temperature dependence of emission spectra of Pr3+ in the Pr(3+)-doped SrAl12O19 was well explained.
