The aim of this work is to develop the method to assay activity of laccase and peroxidase in plant and fungal extracts. We use laccase from Trametes versicolor and peroxidase from Armoracia rusticana as model enzymes to select the optimal conditions and to get the kinetic data by spectrophotometrical method. The approach was tested on assay the laccase and peroxidase activity in protein precipitate, isolated from aqueous extract of mycelial-sybstrate complex (solid-state culture) of Pleurotus ostreatus, strain HK-35. Meaning the different substrate specifity of isoenzymes in natural objects, use the different types of substrates (heterocyclic compounds, aromatic amines, phenols) improves reability of activity assay. Application of chemiluminescence to assay the enzymatic activity allows to work with mucous and highly colored samples, when spectrophotometry is difficult. In contrast to traditional luminol-depended chemiluminescent methods to peroxidase activity assay, the current study discover luminescence by oxidation the polyhidric phenols without activators. All used substrates except the phenol oxidise in presence of extracellular enzymes of strain HK-35, P. ostreatus. During oxidation of floroglucinol by these enzymes, as well as model enzymes take place chemiluminescence.