US EPA

2748801 

Journal Article 

EPR kinetic studies of superoxide radicals generated during the autoxidation of 1-methyl-4-phenyl-2,3-dihydropyridinium, a bioactivated intermediate of Parkinsonian-inducing neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine 

Zang L-Y; Misra, HP 

1992 

Yes 

Journal of Biological Chemistry
ISSN: 0021-9258
EISSN: 1083-351X 

BIOSIS/93/04395 

267 

33 

23601-23608 

English 

BIOSIS COPYRIGHT: BIOL ABS. 1-Methyl-4-phenyl-2,3-dihydropyridinium (MPDP+), a metabolic product of the nigrostriatal toxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), has been shown to generate superoxide radicals during its autoxidation process. The generation of superoxide radicals was detected as a 5,5-dimethyl-1-pyrroline-N-oxide (DMPO)in trapping in combination with EPR techniques. The rate of formation of spin adduct was dependent not only on the concentrations of MPDP+ and oxygen but also on the pH of the system. Superoxide dismutase inhibited the spin adduct formation in a dose-dependent manner. The ability of DMPO to trap superoxide radicals, generated during the autoxidation of MPDP+, and of superoxide dismutase to effectively compete with this reaction for the available O2-, has been used as a convenient competition reaction to quantitatively determine various kinetic parameters. Thus, using this technique the rate constant for scavenging of superoxide radical by superoxide di