Hydrolytic and chromatographic studies on the PEGylation of dextranase from Penicillium sp.

Dextranases catalyze the hydrolysis of the α-l,6-glucosidic bond of the polysaccharide dextran. Dextranases have been isolated from bacteria, yeast and fungi. Purified dextranase enzyme from Penicillium sp. was PEGylated (polyethylene glycol modification) with mPEG (5000 Da) and showed an increase in the dextranase protein molecular weight as estimated by Superose 12 (23 ml) column and this increment in the molecular weight is directly proportional to mPEG (5000 Da) concentration until a complete dextranase enzyme PEGylation (disappearance of dextranase peak). The residual activity of partially PEGylated dextranase (mPEG 5000 of 5.8 mg/ml) was 33.8% and for the completely PEGylated dextranase (mPEG 5000 of 29 mg/ml) it was 25.75%. Dextranase PEGylated with mPEG (30,000 Da) showed a little PEGylation at mPEG concentration of 5.8 mg/ml but at a concentration of 29 mg/ml several PEGylated peaks were produced with a difference in dextranase activity toward dextran T500, retardation in the activity with the increasing in the molecular weight was clearly appeared with Sephadex G75 but for Sephadex G200 a little retardation than Sephadex G75 has been appeared.