Phenol oxidase molecular weight

Gottlieb and Geller (34) reported further to have obtained an enzyme preparation from mushroom spawn, which they claim to catalyze a reaction between native lignin and oxygen. They believe that this enzyme is different from other phenol oxidases heretofore studied. It was later reported that the enzyme acts on low molecular weight water soluble compounds closely related to native lignin. The nature of these compounds was, however, not determined (35). 

One of the major chemical properties of the phenolic acids is the ease with which they oxidize. In the presence of oxygen, chlorogenic acid, caffeic acid and other related o-diphenols can oxidize by the action of polyphenol oxidase or in alkaline solution. These polyphenol oxidases are copper-containing proteins and are widespread in nature. Some of them oxidize only selected o-dihydroxyphenols while others, such as tyrosinase, not only oxidize dihydroxyphenols but convert monohydroxyphenols, such as tyrosine, to oxidizable dihydroxyphenols. The quinones formed are highly reactive substances which normally react further with other quinones to produce coloured compounds of high molecular weight. They may also react however with lysine, methionine, cysteine and tryptophan residues in the protein chain (Fig. 1). 

Biocatalysts (oxidative enzymes) this enzyme system consists of peroxidases, such as manganese peroxidase, Ugnin peroxidase and other peroxidases, phenol oxidases, such as laccases, and various low-molecular-weight agents, such as oxalate and malate. 

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