Alternative Oxidase of Potato Is an Integral Membrane Protein Synthesized de Novo during Aging of Tuber Slices

The rise in alternative respiratory capacity upon aging of potato (Solanum tuberosum) tuber slices is correlated with changes in mitochondrial membrane protein composition and a requirement for cytoplasmic protein synthesis. However, the lack of an antibody specific to the alternative oxidase has, until recently, prevented examination of the alternative oxidase protein(s) itself. We have employed a monoclonal antibody raised against the Sauromatum guttatum alternative oxidase to investigate developmental changes in the alternative pathway of aging potato slice mitochondria and to characterize the potato alternative oxidase by one- and two-dimensional gel electrophoresis. The relative levels of a 36 kilodalton protein parallel the rise in alternative path capacity. A plausible interpretation is that this alternative oxidase protein is synthesized de novo during aging of potato slices.