This experiment was carried out to evaluate the inhibition of the 1-aminocyclopropane-1-carboxylic acid (ACC) oxidase in apple fruits by controled atmosphere. Jonagold apples were stored in normal atmosphere (NA) and controlled atmosphere (CA) storage. The fruits were harvested at the preclimateric stage and stored for 120 days at 0ºC and 95±5% RH with O2 set to 1,5% and CO2 set to 2,5% (CA) or without gas control (NA). At 90 and 120 days after harvesting, samples were collected to study the ethylene production by gas chromatography, ACC oxidase activity by gas chromatography and immunoblotting protein characterization by western blot, using specific polyclonal antibodies against ACC oxidase from apple fruit. Nevertheless, ACC oxidase was detected and the ethylene production was increased for those fruits stored by 120 hours under room temperature. Apples stored in NA did not control the ethylene production and ACC oxidase synthesis. However, apples stored in CA had the ethylene biosynthesis controlled and showed an ACC oxidase synthesis inhibited. In climacteric apples, the ACC oxidase activity increased by ACC, Fe+2 and ascorbat addition in the enzymatic extract. Protein analysis by isoelectricfocusing showed three proteins with pIs 5.95, 5.87 and 5.78. Those with smallers pIs were detected in the presence of substrate and cofactors.
ripening; isoforms; apple storage
