Protein glycosylation, a major post-translational modification, plays essential roles in eukaryotic cells. The glycosylation of fungal laccases has been proposed to be the bottleneck for the heterologous product ion of the enzyme, so it is important to determine its structure and function. We describe here the detailed N-glycosylation profile of Pycnoporus sanguineus laccase and its influence on some of its enzymatic properties. In this enzyme only high mannose structures were found, being those with 5- and 8-mannose units the most abundant. No other type of sugars was found in contrast to other fungal laccases. Enzymatic cleavage of the N-glycans present in the laccase provoked slight changes in the kinetic parameters, in the thermal stability and in the pH optimum of the enzyme. (C) 2009 Elsevier Inc. All rights reserved.