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 ...

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 ...

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 ...

Adulteration of propolis with poplar extract is a serious issue in the bee products market. The aim of this study was to identify marker compounds in adulterated propolis, and examine the transformation of chemical components from poplar buds to propolis. The chemical profiles of poplar extracts and propolis were compared, and a new marker compound, catechol, was isolated and identified from th...

The seed coat of Pisum elatius is normally impermeable to water. When seeds are dried in the absence of oxygen their coats are totally permeable to water. Structural differences are observed between permeable and impermeable seed coats. In the genus Pisum, species with normally impermeable seed coats have a high content of phenolics and of catechol oxidase, while seed coats of P. sativum contai...

It is reported that chlorogenic acid is widely distributed in plants (7) and is the principle polyphenol in tobacco leaves (8). When the tissues of the tobacco plant are injured, the polyphenols are oxidized and then polymerize, forming a brown pigment. This oxidation is reported to be catalyzed by polyphenol oxidase. Polyphenol oxidase has been identified in many species of plants and the enzy...

Catechol oxidase (EC 1.10.3.1), tyrosinase (EC 1.14.18.1), and laccase (EC 1.10.3.2) are copper-containing metalloenzymes. They oxidise substituted phenols and use molecular oxygen as a terminal electron acceptor. Catechol oxidases and tyrosinases catalyse the oxidation of p-substituted o-diphenols to the corresponding o-quinones. Tyrosinases also catalyse the introduction of a hydroxyl group i...

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...

The distribution of catechol-O-methyl transferase and monoamine oxidase activity in the ocular tissues of albino rabbits has been determined with a radioactive tracer assay. The distribution of the former varied in the different tissues within a restricted range whereas the distribution of monoamine oxidase activity exhibited larger variations. Sympathetic denervation did not appear to affect c...