EN
Ascorbate peroxidase (APX) is one of the key enzymes of the plant antioxidant system playing, along with catalase, a central role in hydrogen per oxidescavenging. An approach to further in crease the knowledge about cytosolic APX gene organization can be achieved by isolating and characterisating new cDNAs, thus providing new in sights about the physiological roles and regula tion of these enzymes. A partial cDNA clone (corresponding to the 3’ untranslated region), cytosolic ascorbate peroxidase-re lated, was isolated from potato sprouts by RT-PCR. Data base analysis re trieved several expressed sequence tags (ESTs) coding potato cytosolic ascorbate peroxidase, that were used to infer the complete cDNA sequence. The deduced amino acid sequence revealed high homologies with other plant cytosolic ascorbate peroxidases, con firming the reliability of the vir tual cDNA. Northern blot analysis revealed the existence of a single band related to the isolated cDNA and the southern blotting results al lowed the elaboration of a possible gene organization.