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Titolo:
Characterization of monophenolase activity of polyphenol oxidase from iceberg lettuce
Autore:
Chazarra, S; Garcia-Carmona, F; Cabanes, J;
Indirizzi:
UnivE-30071, Dept Bioquim & Biol Mol A, Unidad Docente Biol, Edificio Vet,Univ Murcia Murcia Spain E-30071 l A, Unidad Docente Biol, Edificio Vet,
Titolo Testata:
JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY
fascicolo: 4, volume: 47, anno: 1999,
pagine: 1422 - 1426
SICI:
0021-8561(199904)47:4<1422:COMAOP>2.0.ZU;2-I
Fonte:
ISI
Lingua:
ENG
Soggetto:
LACTUCA-SATIVA; ENZYMATIC OXIDATION; L-SERINE; TYROSINASE; 4-METHYLCATECHOL; MELANIZATION; PURIFICATION; DOPACHROME; PATHWAY; DOPA;
Keywords:
plant polyphenol oxidase; lettuce; Lactuca sativa; monophenolase activity;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Agriculture,Biology & Environmental Sciences
Life Sciences
Citazioni:
27
Recensione:
Indirizzi per estratti:
Indirizzo: Cabanes, J UnivCampusa, Dept Bioquim & Biol Mol A, Unidad Docente Biol, Edificio Vet, Univ Murcia Campus Espinardo Murcia Spain E-30071 dificio Vet,
Citazione:
S. Chazarra et al., "Characterization of monophenolase activity of polyphenol oxidase from iceberg lettuce", J AGR FOOD, 47(4), 1999, pp. 1422-1426

Abstract

Polyphenoloxidase (EC 1.14.18.1), a thylakoid membrane-bound enzyme, was isolated by sonication of osmotically shocked chloroplasts from iceberg lettuce (Lactuca sativa). The enzyme showed monophenolase activity when assayedon (p-hydroxyphenyl)propionic acid with 3-methyl-2-benzothiazolinone hydrazone in a reliable continuous spectrophotometric method, with high sensitivity, accuracy, and precision. The monophenolase activity showed a lag period before the steady-state rate (V-ss) was reached. Both kinetic parameters,the lag period and the steady-state rate, depended on the pH, the enzyme and substrate concentrations, and the presence of catalytic amounts of o-diphenol. This activity shows inhibition by high substrate concentration. The experimental results correspond with the mechanism previously described forPPO from other sources. Kinetic constants K-m, V-max, and K-i were determined.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 05/12/20 alle ore 20:11:58