This research investigated the role of oxidative enzymes in the defense response of sorghum, Sorghum bicolor (L.) Moench (Poales: Poaceae), to the sorghum shoot fly, Atherigona soccata Rondani (Diptera: Muscidae). Changes in polyphenol oxidase and peroxidase activity and total protein content were observed in resistant and susceptible sorghum genotypes in response to A. soccata feeding. Resista...

The mechanism whereby light effects polyphenol oxidation was examined with Vicia faba chloroplast membranes known to contain a bound latent polyphenol oxidase. Results obtained with the inhibitors 3-(3',4'-dichlorophenyl)-1,1-dimethylurea (DCMU) and 2,5-dibromo-3-methyl-6-idopropyl-p-benzoquinone (DBMIB) indicated an involvement of the non-cyclic electron transport pathway in the light-dependen...

In order to better understand how to prevent enzymatic greenning, it is important to understand  kinetic properties of polyphenol oxidase.  we investigated the effect of SDS on the rate of catechol oxidation by small cherry tomato partial purified PPO. PPO activity increased with increasing SDS concentration. The most effective concentration of SDS was 0.8, 1 and 1.25 mM in according to pH and ...

to evaluate and compare the chlorophyll content, carotenoid, protein, peroxidase and polyphenol oxidase in different barley species in iran, 49 genotypes belonging to 5 barley species were employed in a completely randomized design with three replications in greenhouse conditions. a high level of within and between species variation was detected. in all the species, significant positive correla...

We report here a novel bioelectrode based on self-assembled multilayers of polyphenol oxidase intercalated with cationic polyallylamine built up on a thiol-modified gold surface. We use an immobilization strategy previously described by Hodak J. et al. (Langmuir 1997, 13, 2708-2716) Quartz crystal microbalance with electroacustic impedance experiments were carried out to follow quantitatively t...

Phloroglucinol and resorcinol are not substrates for clingstone peach (Prunus persica) polyphenol oxidase, but they react with 4-methyl-o-quinone, produced either enzymatically or nonenzymatically, to give an intense red or red-brown color with a maximal absorption at about 470 nanometers. Several colored products were isolated from an ethyl acetate extract of the reaction by two-dimensional th...

In order to better understand how to prevent enzymatic greenning, it is important to understand  kinetic properties of polyphenol oxidase.  we investigated the effect of SDS on the rate of catechol oxidation by small cherry tomato partial purified PPO. PPO activity increased with increasing SDS concentration. The most effective concentration of SDS was 0.8, 1 and 1.25 mM in according to pH and ...

1. The distribution of polyphenol oxidase in quinone-tanning systems may be demonstrated in frozen-dried sections by incubation in 0-2 per cent, aqueous catechol at 40 C. for 15-60 minutes. A red colour develops at the enzyme site. 2. The evidence for the view that the egg-shell in trematodes, in certain cestode groups, and in turbellarians, is a quinone-tanned protein secreted by the so-called...