Characterization of an unglycosylated low molecular weight 1,4-beta-glucan-glucanohydrolase of Trichoderma reesei.
A low molecular weight endoglucanase (1,4-beta-glucan glucanohydrolase E.C.3.2.1.4) was purified to homogeneity by a two-step procedure from 7 day old culture filtrates of Trichoderma reesei. The endoglucanase was obtained by BioGel A 0.5 m gel chromatography followed by preparative PAGIF. The purified endoglucanase was homogeneous upon titration curve separation. Enzyme characteristics were: Mr 25 kDa, pI 7.5. The amino acid composition is predominantly neutral (mainly glycine). The N-terminus is arginine. The pH-optimum for this endoglucanase was 5.8 and its optimal temperature was at 52 degrees C. The activity of this endoglucanase gave a strong increase in CMC-fluidity with only a small release of reducing sugars. The endoglucanase was 0.2% of total culture medium protein content. The reducing sugars upon CMC digestion were G1-G4. The enzyme had no specificity towards crystalline cellulose (Avicel) or xylan. The endoglucanase is not a glycoprotein.
Institut für Biotechnologie der Kernforschungsanlage Jülich, F.R.G.
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Ulker
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Sprey
D000596:Amino Acids / Q000032:analysis; D002480:Cellulase / Q000032:analysis / Q000302:isolation & purification / Q000378:metabolism*; D002850:Chromatography, Gel; D006863:Hydrogen-Ion Concentration; D008970:Molecular Weight; D013696:Temperature; D014242:Trichoderma / Q000201:enzymology*; D014461:Ultracentrifugation
D000596:Amino Acids; D002480:Cellulase