As revealed by qualitative and quantitative analyses of the protein and carbohydrate moieties, the microheterogeneity of the glycoprotein laccase I1 is caused by quantitative differences within the carbohydrate part. Assuming that there is a constant binding of the carbohydrate chain via N-acetylglucosamine to the polypeptide, it would appear that the unequal content of sugars in the various fractions of laccase I1 corresponds to an unequal length of its carbohydrate chains, which gradually varies between a maximum and minimum value.

In order to investigate the extent of the relationship between the three copper-containing glycoproteins, laccases I, I1 and I11 ( M I 70000,80000 and 390000 respectively) of Podospora anserina, the following experiments were carried out on laccases I1 and 111: (a) determination of amino acid composition ; (b) determination of N-terminal and C-terminal amino acid ; (c) determination of sugar composition; (d) dissociation studies on native and denatured laccases and also after removal of copper from the enzymes; (e) digestion of the carbohydrate moieties with the aid of glycosylhydrolases.A comparison between the results of these experiments and data previously obtained with laccase I allows the following conclusions to be drawn.

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