, Volume 103, Issue 1, pp 271-277

Function of enzymes in wood destroying fungi

Rent the article at a discount

Rent now

* Final gross prices may vary according to local VAT.

Get Access

Abstract

Laccases (p-diphenol-O2-oxidoreductases E.C. 1.14.18.1) of 15 wood rotting fungi were separated by analytical and preparative isoelectric focusing (IEF). Most of the fungi exhibit a pattern of 6–10 extra- and intracellular laccases. A group of laccase bands at pH 3–4 (A complex) and at pH 5–8 (B complex) was common.

The laccase isoenzymes showed a qualitative variability with respect to substrate specificities when tested with ortho-, meta- and para-phenolic compounds. There were also differences between intra- and extracellular laccases having identical isoelectric points.

This reaction pattern became more complicated when peroxide was added to the enzyme substrates, showing that in some cases it is not possible to make a clear distinction between laccase and peroxidase activity.

A quantitative assay of substrate specificities with a polarographic method revealed no gross differences between the two strains tested but a preference for ortho- and paraphenols, whereas meta-phenols are less accessible by laccases.

Laccase patterns of 6 geographical races of Pleurotus ostreatus were compared. Inspite of its complexity, there were only slight differences showing their close relationship. In contrast, no comparable agreements have been found between inter-species laccase patterns. The validity of protein or enzyme patterns for taxonomical studies is discussed.

Due to the large versatility of the laccase patterns it is concluded that, of the species tested, Polyporus brumalis and Leptoporus litschaueri are best suited for further studies of the laccase function in wood destroying fungi.