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PURIFICATION AND KINETIC CHARACTERIZATION OF POLYPHENOL OXIDASE FROM TOMATO FRUITS ( LYCOPERSICON ESCULENTUM CV. MUCHAMIEL)
Author(s) -
CASADOVELA J.,
SELLÉS S.,
BRU R.
Publication year - 2005
Publication title -
journal of food biochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.507
H-Index - 47
eISSN - 1745-4514
pISSN - 0145-8884
DOI - 10.1111/j.1745-4514.2005.00037.x
Subject(s) - lycopersicon , polyphenol oxidase , chemistry , catechol oxidase , substrate (aquarium) , enzyme , yield (engineering) , polyphenol , ammonium , fractionation , chromatography , particulates , food science , biochemistry , botany , antioxidant , biology , organic chemistry , materials science , peroxidase , ecology , metallurgy
Two different polyphenol oxidase (PPO) fractions, soluble and particulate, were purified from unripe tomato fruits ( Lycopersicon esculentum M. cv. Muchamiel). The PPO present in the soluble fraction was purified fivefold with a 43.5% yield after ammonium sulfate fractionation. PPO in the particulate was purified 4.56‐fold with a 23% yield using the nonionic detergent Triton X‐114. A strong correlation between tomato fruit PPO activity and the physiological disorder blossom‐end rot (BER) was found, with a large increase of the PPO activity in the particulate fraction. Kinetic characterization, including kinetic parameters, pH and temperature profiles, substrate specificity and inhibitors showed similarities in both the soluble and the particulate enzyme(s). However, thermal stability of the particulate enzyme was significantly higher than stability of the soluble PPO, thus indicating possible structural differences. Cupric ions were activators, probably because of their ability to reactivate PPO partly denatured during purification.