TECHNOLOGY FOCUS - BIOLOGY - Preferred Component: The isolated polynucleotide comprises nucleotide sequence (SEQ ID NO:9) or (SEQ ID NO:11) or a sequence with greater than or equal to 70% sequence identity. The amino acid sequence has been N terminally and/or C terminally truncated.Preferred Material: The filamentous fungus is Trichoderma sp. The enzyme is a cellulase. The organism is a yeast or bacterial cell.Preferred Parameter: The degradation is performed in a medium with a pH of 4.5-5.5. EXAMPLE - T. reesei was grown in corn steep liquor enriched medium as clescnoea. Endo T activity was monitored on filtered supernatant from growing cells. Endo T Activity was present from the beginning of the cultivation. Because of the low production of Endo T activity in the medium (2.51 mU/ml), culture growth was stopped just before the secretion of cellulases. Endo T is an enzyme found in the culture medium and not in the cells, indicating that Endo T is secreted. Using Man5GIcNAc2-RNase B as substrate, the endo-D-N-acetylglucosaminidase was purified 1300-fold from the culture medium of T. reesei. The Avicel adsorption step was efficient in removing carbohydrate binding module containing proteins (cellulases) and facilitated the subsequent purification but resulted in a substantial loss of activity (61%). This was probably due to affinity of the Endo T protein for the glycosylated cellulases bound to Avicel, but 14-fold enrichment was obtained during this first purification step. The non-bound fraction was applied to a DEAE-sepharose -FF column, which was subsequently eluted with a linear gradient of 5-300 mM ammonium oxyacetate, pH 5. Proteins were monitored at 280 nm, and the Endo T activity was assayed with the FITC-labeled glycoproteins. The purification was also monitored by activity measurements on invertase (10 mul of the fractions were incubated with 10 mul 10mg/ml substrate dissolved in 100 mM sodium acetate buffer pH 5). Activity as followed by 7.5% sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The enzyme activity eluted at high acetate concentration and was pooled. This purification step resulted in a substantial enrichment (172 fold) and almost no loss of activity.