Charge Properties of Mitochondrial Matrix Proteins
Proteins of the rat liver mitochondrial matrix have been separated into anionic (acidic), cationic (basic), and neutral groups by electrophoresis. These groups represent 69, 8, and 23% of the total matrix protein, respectively, compared to 69, 21, and 10% for the cytosol protein. The acidic nature of the mitochondrial matrix proteins has been confirmed by cellulose ion-exchange chromatography, isoelectric focusing in sucrose gradients, and amino acid analysis. The anionic, cationic, and neutral matrix proteins were separated by sodium dodecyl sulfate – polyacrylamide gel electrophoresis into 18, 6, and 5 bands, respectively, compared to 22 bands for the total fraction. The significance of the charge properties of these proteins in terms of mitochondrial biogenesis is discussed.