Distribution of glutathione peroxidases and glutathione reductase in rat brain mitochondria.

The distribution of glutathione reductase (GR), glutathione peroxidase (GPx) and phospholipid hydroperoxide glutathione peroxidase (PHGPx) in isolated rat brain mitochondria was investigated, using a fractionation procedure for the separation of inner and outer membranes, contact sites between the two membranes and a soluble fraction mainly originating from the mitochondrial matrix. The data indicate that GR and GPx are concentrated in the soluble fraction, with a minor portion of the two enzymes being associated with the contact sites. PHGPx is localized largely in the inner membrane. The possible functional significance of these findings is discussed.