Ethylene formation from 1-aminocyclopropane-1-carboxylic acid in plant mitochondria

AbstractMitochondria isolated from apical parts of etiolated pea seedlings convert ACC to ethylene. This conversion is heat-sensitive and largely enhanced when the intact mitochondria are sonicated or when the ionophore nigericin is added to the reaction medium. When the sonicated submitochondiral particles are spun down, almost all of the activity is recovered in the pellet. The results suggest that the ethylene-formation activity is associated with the inner mitochondrial membrane and that transport of ACC into the mitochondrial membrane is a rate limiting step for the reaction. The mechanism of ACC transport across the mitochondrial membrane is discussed