INCREASED STABILITY OF PEG-PPG CONJUGATED HUMAN UROKINASE AGAINST AUTOLYSIS

Human urokinase (UK) was easily degraded during the incubation at 37 d egrees C in a time-dependent manner, The degradation was also observed in the presence of trypsin inhibitors, suggesting that UK was not deg raded by exogeneous trypsin-like serine protease but by autolysis, In this cases, the A-chain of UK was selectively degraded, Polyethylene g lycol-polypropylene glycol conjugated urokinase (PEG-PPG-UK) was not d egraded after prolonged incubation at 37 degrees C, These results demo nstrated that PEG-PPG modification completely blocked the degradation of UK by autolysis.