IMMUNOCHEMICAL AND IMMUNOHISTOCHEMICAL STUDY OF APPLE CHLOROGENIC ACID OXIDASE

Mouse antibody was raised against chlorogenic acid oxidase from apple (Malus pumila cv. Fuji). This antiserum was used for immunochemical characterization of the enzyme of apple and other plants and then for the immunocytolocalization of the enzyme in apple fruit to clarify the relationship between the distribution of the enzyme and browning. Western blot analysis revealed that the antibody recognized only the purified enzyme from apple fruit, with a molecular weight of 65 000. All of the apple cultivars showed the same band as the purified enzyme of Fuji. When the cross-reactivity of polyphenol oxidase between apple and other plants was examined, the antiserum only recognized the enzyme of pear. The browning of the apple fruit sections was predominantly observed around the core. Likewise, chlorogenic acid oxidase was also localized mainly near the core as shown by the nitrocellulose tissue print method using immunostaining.