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

Dopamine during in vitro oxidation induced covalent cross-linking of membra ne proteins in rat brain crude mitochondrial-synaptosomal fraction. The pro cess is not inhibited by hydroxyl radical scavengers, lipid soluble anti-ox idants, metal-chelator or catalase, but reduced glutathione produced a dram atic inhibition of cross-linking. The protein cross-linking mediated by dop amine is not associated with any detectable membrane lipid peroxidation but significant formation of protein bound quinone takes place during incubati on. Our results indicate that reactive quinones rather than oxygen free rad icals are involved in dopamine induced protein cross-linking in rat brain m embrane fraction. (C) 2001 Elsevier Science B.V. All rights reserved.