Chemical modification of E. coliL-asparaginase with polyethylene glycol grafted vinylpyrrolidone–maleic anhydride copolymer
✍ Scribed by Guoqiang Qian; Jianbiao Ma; Juyan Zhou; Binglin He; Daobin Wang
- Publisher
- John Wiley and Sons
- Year
- 1997
- Tongue
- English
- Weight
- 304 KB
- Volume
- 8
- Category
- Article
- ISSN
- 1042-7147
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✦ Synopsis
A series of polyethylene glycol grafted vinylpyrrolidonemaleic anhydride copolymers [P(VMP)] was synthesized by radical copolymerization of vinylpyrrolidone, maleic anhydride and polyethylene glycol maleic acid monoester. Escherichia coli L-asparaginase was chemically modified with these copolymers. The modified L-asparaginase exhibited the complete loss of antigenicity towards anti-asparaginase serum from rabbit. The highest enzyme activity of the modified L-asparaginase without antigenicity was retained by 59% of the nonmodified one. The modified enzyme was also more resistant to trypsin in vitro. When tested in vivo, the native L-asparaginase was quickly cleared from the plasma of rabbits (half-life time: t 1/2 = 1.2 hr), whereas the modified enzyme showed prolonged clearance from plasma (t 1/2 = 53 hr).