Uniform poly(isopropylacrylamide) gel beads for immobilization of α-chymotrypsin

✍ Scribed by M. Bayhan; A. Tuncel

• Publisher: John Wiley and Sons
• Year: 1998
• Tongue: English
• Weight: 309 KB
• Volume: 67
• Category: Article
• ISSN: 0021-8995
• DOI: 10.1002/(sici)1097-4628(19980207)67:6<1127::aid-app21>3.0.co;2-w

✦ Synopsis

In this study, a-chymotrypsin was immobilized via physical entrapment within large, uniformly spherical, and thermally reversible poly(N-isopropylacrylamide) [poly(NIPAM)] beads. The gel beads were prepared in an aqueous dispersion medium by using Ca-alginate gel as the polymerization mold. In this preparation, potassium persulfate/tetramethylethylenediamine and sodium-alginate/calcium chloride were used as the redox initiator and the stabilizer systems, respectively. Thermoresponsive poly(NIPAM) gel beads 3 mm in size and including a-chymotrypsin were produced by the proposed procedure. The use of an aqueous bead-forming medium did not cause significant enzyme leakage during the preparation of enzyme-gel beads. Michaelis-Menten kinetics was used to define the behaviors of enzyme-gel beads prepared with different enzyme loadings. The Lineweaver-Burk plot indicated that the enzyme-gel system had a reasonably higher K m value relative to that of free enzyme due to the internal mass transfer resistance against the substrate diffusion. The enzyme-gel system exhibited the maximum activity at 30ЊC due to the thermoresponsive character of the carrier matrix. However, the maximum activity with the free enzyme was observed at 40ЊC.