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KMID : 0370220070510030199
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Yakhak Hoeji
2007 Volume.51 No. 3 p.199 ~ p.205
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Thermostability and Resistance to Proteolysis of L-Asparaginase Purified from Strepfomyces lincolnensis M-20
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Kim Kyoung-Ja
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Abstract
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Thermostable asparaginase was purified to homogeneity from mesophilic Strepfomyces lincolnensis M-20 by 30~70% ammonium sulfate precipitation and asparagine-Sepharose CL 6B affinity column chromatography, The apparent molecular mass of L-asparaginase by SDS-PAGE was found to be 47 kDa, whereas by its mobility on Sephacryl S-300 column was around 180 kDa, indicating that the enzyme at the native stage acts as tetramer, The purified enzyme showed a single band on acrylamide gel electrophoresis. The optimum pH and temperature were pH 9.5 and 55℃, respectively. Chemical modification experiments of purified asparagines implied the existence cystein residue located at or near active site. Purified asparaginase retained the 85% of the initial activity after incubation at 90℃ for 30 min. A correlation between themostability and resistance to proteolysis of commercial asparaginase and purified asparaginase from Strepfomyces lincolnensis M-20 was investigated. Purified thermostable asparaginase was resistant to trypsin and chymotrypsin treatment, while the commercial asparaginase was not themostable and was susceptible to proteolytic treatment with trypsin and chymotrypsin.
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KEYWORD
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themostability, resistance to proteolysis, asparaginase, Strepfomyces lincolnensis M-20
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