Reduction of cytochrome c by fragments of heat shock protein 70

Using absorption spectroscopy, we have found that two highly conserved fragments of heat shock protein 70 reduce cytochrome c. The fragments are SCV and YSCVGVF. YSCVGVF was more potent than SCV at low concentrations (10(-6)-10(-4)M). At high concentrations (5 x 10(-4)-10(-3)M) SCV was more potent than YSCVGVF. Reduction of CC by YSCVGVF was reversed by cytochrome c oxidase. These findings show that heat shock protein 70 and/or small intracellular peptides could carry electrons to cytochromes.