Modified alginate matrices for the immobilization of bioactive agents
| Autor: | Monique Lacroix, Mathieu Millette, Mircea-Alexandru Mateescu, Canh Le-Tien |
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| Rok vydání: | 2004 |
| Předmět: |
Immobilized enzyme
Alginates Biomedical Engineering Bioengineering Biocompatible Materials Applied Microbiology and Biotechnology Enzyme activator chemistry.chemical_compound Biopolymers Drug Discovery Enzyme Stability Materials Testing Nisin chemistry.chemical_classification Chromatography biology Peptide stabilization Sodium periodate Process Chemistry and Technology Temperature food and beverages Substrate (chemistry) General Medicine Hydrogen-Ion Concentration Catalase Enzymes Immobilized Enzyme assay Enzyme Activation Kinetics Enzyme chemistry Biochemistry biology.protein Molecular Medicine Adsorption Biotechnology |
| Zdroj: | Biotechnology and applied biochemistry. 39(Pt 2) |
| ISSN: | 0885-4513 |
| Popis: | Bioactive agents (catalase - an enzyme, and nisin - a bacteriocin) were covalently immobilized on alginate activated with sodium periodate (oxidatively converting 2,3-dihydroxy groups into dialdehyde residues), followed or preceded by ionotropic gelation. For the same protein coupling yield, the retained enzyme activity of the immobilized enzyme (ImE) can be markedly increased by diminishing the bead diameter, a phenomenon that illustrates the role of substrate/product diffusion through the bead gel layer. When the amount of enzyme introduced for coupling was about 15 mg/100 mg of support and the bead diameter was about 100 microm, a high retained specific activity (95-98%) was obtained. Diffusion phenomena can be markedly decreased by enzyme immobilization on the surface of microbeads (obtained by gelation of activated alginate prior to immobilization). In this case, the retained activity was approx. 75% of that of the free enzyme. A slightly higher K (m) value of ImE suggested that the enzyme-substrate affinity was almost maintained. The profiles of ImE activities at various pH values, at various temperatures and when undergoing proteolysis showed a overall higher stability for the immbolized than that for the free enzyme. Nisin immobilized on the microbead surface, when submitted to proteolysis, conserved its bacteriocin activity, strongly inhibiting the growth of Lactobacillus sake when subjected to an agar spot test, whereas free nisin totally lost its activity. |
| Databáze: | OpenAIRE |
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