Alterations in Solanum tuberosum polyphenol oxidase activity induced by gamma irradiation

On gamma irradiation of potato tubers at sprout-inhibiting dose (10 krad) the cresolase activity showed a 45% increase while catecholase was reduced by 25%. This reduced the ratio of catecholase to cresolase from 11–12 in unirradiated to 5–6 in irradiated potatoes. Chlorogenic acid oxidation was enhanced by about 25% on irradiation. The increase in the oxidation of p-cresol corresponded with the production of diphenolic compounds. The process of activation of cresolase was slow, reversible and oxygen dependent. A comparative study of the isoenzyme pattern suggested that this activation was due to conformational change, rather than synthesis of new protein.