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Optimization of Asparaginase Immobilization on Carrier

Bahraman, Fatemeh | 2009

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 46348 (06)
  4. University: Sharif University of Technology
  5. Department: Chemistry Engineering
  6. Advisor(s): Alemzadeh , Iran; Kazemi, Akhtarolmolok
  7. Abstract:
  8. The enzyme L-asparaginase (L-asparagine amidohydroxylase , EC 3.5.1.1) is utilizable in the treatment of acute childhood lymphoblastic leukaemia. L-asparaginase catalyses the hydrolysis of the amino acid L- asparagines to L-aspartic acid and ammonia. Unlike normal cells,malignant cells which can only slowly synthesize L-asparagine , are killed by lacking exogenous supply. In contrast, normal cells are protected from Asn-starvation due to their ability to produce this amino acid.
    In this study , L- asparaginase from E.coli, was immobilized onto a polymeric compound, poly(vinyl alcohol)(PVA) with cross-linking agent glutaraldehyde and calcium alginate beads .. Herein ,with the use of the different concentrations of glutaraldehyde, the effect of matrix concentration and with the use of the different speeds for shaking, the effect of physical parameters were studied on immobilization efficiency. Response surface methodology (RSM) and central composite design(CCD) were used to optimize immobilization of anti-leukaemia L-asparaginase from E. coli onto calcium alginate beads. Independent variables were the amount of sodium alginate, calcium chloride and enzyme loading. predicted values thus obtained were closed to the experimental value indicating suitability of the model. The optimum immobilization conditions were as follows: sodium alginate concentration 1.98%(w/v), calcium chloride concentration 3.70%(w/v) and enzyme load 46.91%(v/v). The highest residual L-asparaginase activity % (immobilized enzyme activity/ free enzyme activity) obtained was 34.49%
  9. Keywords:
  10. L-Asparginase Enzyme ; Immobilization ; Poly Vinyl Alcohol ; Calcium Alginate

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