| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 592699 | Colloids and Surfaces A: Physicochemical and Engineering Aspects | 2014 | 4 Pages |
•Enzymes were immobilized on magnetic nanoparticles by a methionine-tag system.•Methionine-tagged immobilized enzymes showed 98% residual specific activity.•The system provided orientational immobilization via the formation of Au-S bonds.
We developed a novel technique for immobilizing enzymes on magnetic nanoparticle surfaces by using a methionine-tag system. Au/Fe-oxide composite nanoparticles synthesized through a radiochemical process were used as magnetic nanocarriers. The C-terminus of Tk-subtilisin, a model enzyme, was modified with a methionine tag and mixed with Au/Fe-oxide composite nanoparticles for immobilization via Au-S bonding. Methionine-tagged immobilized enzymes showed 98% residual specific activity, while the untagged enzymes showed 78%. The methionine-tagged immobilized enzymes retained their activities in a wide temperature range of 30–70 °C. Thus, the methionine-tag system provided orientational immobilization via the formation of Au-S bonds, which resulted in structural stability of the immobilized enzymes.
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