A strain of P. cinnabarinus was isolated which decolorized an industrial waste as well as the disazo dye CSB and the vinyl sulfonyl dye RBBR. On purification the phenoloxidase of the enzyme showed all the characteristics of a laccase. The purified laccase from the white-rot fungus rapidly decolorized both dyes. There appeared to be some charge to size variations of laccase during the reactor cycle. It may be hypothesized that the dye may have acted on a proportion of laccase molecules in such a way that it modulated the protein. This could give rise to a conformational change, which may optimize the catalytic site of the enzyme in such a way that it is more easily accessible. As the dye molecule is very small (FW ~ 625) and contains a free aromatic amino group, there could be a possible reaction occurring between a possibly free carboxyl groups of an exposed amino acid of laccase and the amino group of the dye. This would mean that such amino-containing molecules under certain circumstances might behave like amino acids. Such a modulation could possibly explain the presence of an additional acidic band appearing closer to the cathode upon exposure to the dye.
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