Phenolase Phenolic compounds

PPO (known also as catecol oxidase, phenolase or diphenol-oxygen oxidereductase) and POD catalyse the oxidation of o-diphenols to o-diquinones, as in the hydroxylation of monophenols [13]. PPO is located exclusively in the plastids of healthy tissues, while most phenolic compounds are localized in the vacuoles, the two compounds thus being physically separated [13]. 

Phenolase. An enzyme that promotes the oxidation of phenolic compounds. 

Phenolic compounds are also involved in the enzymatic and non-enzymatic browning of food products. The occurrence of browning reactions is often disadvantageous in the majority of fruit processing operations. Chlorogenic acid and catechin serve as the principal substrates for the phenolase complex that is responsible for the enzymic browning exhibited by many fruits and vegetables. 

The polymerisation of phenolic acids is an oxidative process which may be catalysed by enzymes such as phenolase and peroxidase, as well as by inorganic soil components. The enzymic polymerisation of phenolic compounds, studied extensively by Flaig, Martin, Haider and their co-workers, in the context of the formation of humic substances, has been reviewed by... 

The dominant feature of tyrosinase is that it has both cresolase and catecholase activity. Laccase has a very clear catecholase activity, but its cresolase activity is not so clear. Mason, Fowlks, and Peterson (109) used 02 to label 3,4-dimethylphenol during the tyrosinase-catalyzed oxidation of this compound and showed that the source of the oxygen introduced into the phenol in the phenolase reaction was molecular oxygen according to Reaction 1. 

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