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Immobilization of L‐asparaginase into a biocompatible poly(ethylene glycol)‐albumin hydrogel: I: Preparation and in vitro characterization
Author(s) -
JeanFrancois J.,
Fortier G.
Publication year - 1996
Publication title -
biotechnology and applied biochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.468
H-Index - 70
eISSN - 1470-8744
pISSN - 0885-4513
DOI - 10.1111/j.1470-8744.1996.tb00379.x
Subject(s) - ethylene glycol , chemistry , peg ratio , substrate (aquarium) , enzyme , immobilized enzyme , biocompatibility , chromatography , enzyme assay , aspartic acid , matrix (chemical analysis) , biochemistry , pegylation , organic chemistry , polyethylene glycol , amino acid , biology , ecology , finance , economics
The feasibility of the immobilization of Escherichia coli L‐asparaginase into a hydrogel matrix made of poly‐(ethylene glycol) (PEG) and BSA was demonstrated. After immobilization a 200‐fold increase in the Km value was observed. The use of an L‐aspartic acid analogue, carbobenzoxy‐L‐aspartic acid and surface modification by methoxy‐PEG of molecular mass 5 kDa cause a only a slight gain in affinity of the enzyme for its natural substrate. The immobilized L‐asparaginase has an optimal activity over a larger range of pH than the native enzyme, owing to the effect of the matrix. At a physiological pH of 7.3, the immobilized enzyme retained 90% of its activity compared with only 43% for the native form. The immobilized enzyme retained a high proportion of its initial activity, more than 90% after 50 days of incubation at 37 degrees C, even in the presence of its substrate. This may be compared with a half‐life of 2 days observed for native enzyme incubated under the same conditions. These results suggest that the BSA‐PEG matrix can be very useful for enzyme immobilization and, taking into account the good biocompatibility of the matrix, one can expect that this matrix will provide a functional bioreactor for use in vivo.