Purification and Biochemical Characterization of Polyphenol Oxidases from Embryogenic and Nonembryogenic Cotton (Gossypium hirsutum L.) Cells

Author： Kouakou Tanoh Kouadio Yatty Kouamé Patrice Waffo-Téguo Pierre Décendit Alain Mérillon Jean-Michel

Publisher： Humana Press, Inc

ISSN： 0273-2289

Source： Applied Biochemistry and Biotechnology, Vol.158, Iss.2, 2009-08, pp. : 285-301

Disclaimer: Any content in publications that violate the sovereignty, the constitution or regulations of the PRC is not accepted or approved by CNPIEC.

Previous Menu Next

Abstract

Polyphenol oxidases (PPOs) were isolated from cell suspensions of two cultivars of cotton (Gossypium hirsutum L.), and their biochemical characteristics were studied. PPO from Coker 312, an embryogenic cultivar, showed a highest affinity to catechol 20 mM, and PPO from R405-2000, a nonembryogenic cultivar, showed a highest affinity to 4-methylcatechol 20 mM. The optimal pH for PPO activity was 7.0 and 6.0 for Coker 312 and R405-2000, respectively. The enzyme had an optimal temperature of 25 °C and was relatively stable at 20–30 °C. Reducing sodium metabisulfite, ascorbic acid, dithiothreitol, SnCl₂, and FeCl₃ markedly inhibited PPO activity, whereas its activity was highly enhanced by Mg²⁺, Ca²⁺, and Mn²⁺ and was moderately inhibited by Ba²⁺, Cu²⁺, and Zn²⁺. The analysis revealed a single band on the sodium dodecyl sulfate polyacrylamide gel electrophoresis which corresponded to a molecular weight of 55 kDa for Coker 312 and 42 kDa for R405-2000.