Dopamine induced protein damage in mitochondrial-synaptosomal fraction of rat brain.

Dopamine during in vitro oxidation induced covalent cross-linking of membrane proteins in rat brain crude mitochondrial-synaptosomal fraction. The process is not inhibited by hydroxyl radical scavengers, lipid soluble anti-oxidants, metal-chelator or catalase, but reduced glutathione produced a dramatic inhibition of cross-linking. The protein cross-linking mediated by dopamine is not associated with any detectable membrane lipid peroxidation but significant formation of protein bound quinone takes place during incubation. Our results indicate that reactive quinones rather than oxygen free radicals are involved in dopamine induced protein cross-linking in rat brain membrane fraction.