Results 111 to 120 of about 30,882 (162)
Some of the next articles are maybe not open access.
Phytochemistry, 1979
Abstract Recent progress in the study of plant polyphenol oxidases is critically reviewed. Two main groups are recognized: the catecholoxidases and the laccases. Their purification, subcellular location and protein properties are described. Attention is also given to their activation and induction, their function and evolution.
Alfred M. Mayer, Eitan Harel
openaire +1 more source
Abstract Recent progress in the study of plant polyphenol oxidases is critically reviewed. Two main groups are recognized: the catecholoxidases and the laccases. Their purification, subcellular location and protein properties are described. Attention is also given to their activation and induction, their function and evolution.
Alfred M. Mayer, Eitan Harel
openaire +1 more source
Properties of wheat bran polyphenol oxidase
Food / Nahrung, 2004AbstractPolyphenol oxidase (PPO) obtained from wheat bran catalyzed the oxidation of 4‐methyl catechol. Phenolic compounds found naturally in crude extract played role as an endogeneous substrate and activity of crude extract needed correction. Activity versus enzyme concentration gave a linear plot at high substrate concentration whereas a nonlinear ...
Ciğdem, Soysal, Zerrin, Söylemez
openaire +2 more sources
Effect of Polyphenol Oxidase on Deodorization
Bioscience, Biotechnology, and Biochemistry, 1997A mixture of purified polyphenol oxidases (PPO), or acetone powders prepared from fruits and vegetables, and polyphenolic compounds (PPs) totally eliminated a methylmercaptan odor. 2-Methyl-thiochlorogenic acid was isolated from the reaction mixture of methylmercaptan and chlorogenic acid with burdock acetone powder.
O, Negishi, T, Ozawa
openaire +2 more sources
Polyphenol Oxidase from Dominga Table Grape
Journal of Agricultural and Food Chemistry, 2005Dominga grape polyphenol oxidase (PPO) was extracted using phase partitioning with Triton X-114. The enzyme was obtained in latent state and could be optimally activated by the presence of 0.2% sodium dodecyl sulfate (SDS) at pH 6.0. In the absence of SDS, the enzyme showed maximum activity at acid pH. The kinetic parameters of the enzyme at pH 3.0 and
Estrella, Núñez-Delicado +3 more
openaire +2 more sources
Properties of tobacco polyphenol oxidase
Archives of Biochemistry and Biophysics, 1959Abstract The properties of partially purified tobacco leaf polyphenol oxidase have been studied. Evidence is presented to establish that the observed oxidations of catechol, caffeic acid, and chlorogenic acid were, in fact, catalyzed by polyphenol oxidase. Enzyme stability, activation, x-ray inactivation, inhibition, pH optima, substrate specificity,
openaire +2 more sources
Polyphenol Oxidase from Allium sp.
Journal of Agricultural and Food Chemistry, 1997Polyphenol oxidase (PPO) was isolated from Allium sp. PPO showed activity to catechol and dl-dopa (Km values were 25 mM for cathecol and 33 mM for dl-dopa;Vmax values were 666 EU/mL·min for cathecol and 166 EU/mL·min for dl-dopa). Catechol was the most suitable substrate for Allium sp. PPO (lowest Km value).
Tozlu, I, Arslan, O, Temur, A
openaire +2 more sources
Characterization of polyphenol oxidase in coffee
Phytochemistry, 2000Polyphenol oxidase (PPO) was characterized in partially purified extracts of leaves (PPO-L) and fruit endosperm (PPO-E) of coffee (Coffea arabica L.). PPO activity was higher in early developmental stages of both leaves and endosperm of fruits. Wounding or exposure of coffee leaves to methyl jasmonate increased PPO activity 1.5-4-fold.
P, Mazzafera, S P, Robinson
openaire +2 more sources
Recombinant polyphenol oxidases for production of theaflavins from tea polyphenols
International Journal of Biological Macromolecules, 2019Theaflavins (TFs) have attracted much attention due to their various bioactivities in black tea. This paper describes the first trial for enzymatic production of TFs by recombinant polyphenol oxidases (PPOs). PPO genes were cloned from nine species and expressed in E. coli.
Jun, Zeng +4 more
openaire +2 more sources
New Spectrophotometric Assay for Polyphenol Oxidase Activity
Analytical Biochemistry, 1993We describe a convenient and sensitive assay of polyphenol oxidase (PPO, EC 1.14.18.1) consisting of spectrophotometry at 300 nm based on the stoichiometric reaction of cysteine with o-quinones produced during the enzymatic oxidation of phenols. The adduct formed exhibited spectral properties different from those of the parent phenol.
Gauillard, Frederic +2 more
openaire +3 more sources
Polyphenol Oxidase‐Like Nanozymes
Advanced MaterialsAbstract Nanozymes are nanomaterials with enzyme‐like activities. Over the past decade, a steadily growing body of research on polyphenol oxidase‐like (PPO‐like) nanozymes, a subgroup of oxidase‐like nanozymes, has suggested their increasing prominence in nanozymology. Most importantly, PPO‐like nanozymes have developed a unique, well‐
Haolun Gu +6 more
openaire +1 more source