Activation of Polyphenol Oxidase of Chloroplasts 1

AUTOR(ES)

Tolbert, N. E.

RESUMO

Polyphenol oxidase of leaves is located mainly in chloroplasts isolated by differential or sucrose density gradient centrifugation. This activity is part of the lamellar structure that is not lost on repeated washing of the plastids. The oxidase activity was stable during prolonged storage of the particles at 4 C or —18 C. The Km (dihydroxyphenylalanine) for spinach leaf polyphenol oxidase was 7 mm by a spectrophotometric assay and 2 mm by the manometric assay. Polyphenol oxidase activity in the leaf peroxisomal fraction, after isopycnic centrifugation on a linear sucrose gradient, did not coincide with the peroxisomal enzymes but was attributed to proplastids at nearly the same specific density.

Documentos Relacionados

• Spinach Thylakoid Polyphenol Oxidase 1: ISOLATION, ACTIVATION, AND PROPERTIES OF THE NATIVE CHLOROPLAST ENZYME
• Tomato Polyphenol Oxidase (Differential Response of the Polyphenol Oxidase F Promoter to Injuries and Wound Signals).
• Isolation and Characterization of Polyphenol Oxidase Isozymes of Clingstone Peach 1
• Polyphenol Oxidation by Vicia faba Chloroplast Membranes: STUDIES ON THE LATENT MEMBRANE-BOUND POLYPHENOL OXIDASE AND ON THE MECHANISM 1 OF PHOTOCHEMICAL POLYPHENOL OXIDATION
• Studies on Polyphenol Content, Activities and Isozymes of Polyphenol Oxidase and Peroxidase During Air-Curing in Three Tobacco Types 1