[Modification of recombinant asparaginase from Erwinia carotovora with polyethylene glycol 5000].

A method for polyethylene conjugation with recombinant asparaginase has been developed to improve therapeutically important properties of this enzyme. Methoxy-nitrophenyl carbamate of polyethylene glycol with molecular weight 5000 was employed as the modification reagent. Optimization of pegylation procedure allowed achieving high level of the enzyme modification. Under 4.5 molar excess of modification reagent more than 10 molecules of methoxy-polyethylene bound per one asparaginase molecular. The modified asparaginase retained 57% of initial activity. A simple and efficient pegylation procedure described in this work can be used for asparaginase production with improved therapeutic properties.