Год выпуска: 2012 Автор: Sanaa El-Sayed Издательство: LAP Lambert Academic Publishing Страниц: 116 ISBN: 9783659115776
Описание
This study aimed to isolate, purify and characterize L-asparaginase present in some animal tissues. The L-asparaginase (EC 3.5.1.1) produced by chicken livers was isolated and characterized. Different purification steps (including ammonium sulphate fractionation followed by separation on Sephadex G-100 gel filtration and Sephadex G-200 gel filtration) were applied to crude filtrate to obtain a pure enzyme preparation. The enzyme was purified 128.5 ± 0.5 fold and showed a final specific activity of 158.11 ± 5.0 U/mg with a 17.1 ± 8.6 % yield. Sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) of the purified enzyme revealed it was one peptide chain with Mr of 33 kDa while by gel filtration appears to be 36 kDa. The enzyme was very specific to L-asparagine and did not hydrolyze L-glutamine. A Lineweaver-Burk analysis showed a Km value of 1.66 mM toward L-asparagine as substrate and Vmax of 34.47 U. The enzyme showed maximum activity at pH 11.0 when incubated at...