title: Simultaneous refolding, purification and immobilization of xylanase with multi-walled carbon nanotubes.
abstract: Multi-walled carbon nanotubes were used as refolding aid for xylanase unfolded with 8 M urea. The hydrophobic surface of the nanotubes enabled the binding, refolding, purification and simultaneous immobilization of the enzyme. While 55% activity could be regained while working with the denatured form of a purified preparation of xylanase, 92% activity could be obtained with the commercial preparation of xylanase in 8 M urea. These activities were obtained with refolded xylanase bound to the carbon nanotubes. Hence an immobilization efficiency of 0.92 was observed. The FT-IR spectroscopy showed that alpha-helical content of xylanase decreased from 17% to 14%, beta-sheet content increased from 53% to 61% and beta-turns decreased from 20% to 15% upon immobilization on the nanotubes. The refolded xylanase molecule bound to the carbon nanotube gave various secondary structure contents very similar to the bound (to carbon nanotubes) native xylanase.
authors.affiliation: Department of Chemistry, Indian Institute of Technology Delhi, Hauz Khas, New Delhi, 110016, India.
authors.forename: Shweta
authors.initials: S
authors.lastname: Shah
authors.forename: Munishwar N
authors.initials: MN
authors.lastname: Gupta
mesh_terms: D043364:Endo-1,4-beta Xylanases / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism*; D004800:Enzymes, Immobilized / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism*; D037742:Nanotubes, Carbon / Q000737:chemistry*; D017510:Protein Folding; D017433:Protein Structure, Secondary; D017550:Spectroscopy, Fourier Transform Infrared
chemical_list: D004800:Enzymes, Immobilized; D037742:Nanotubes, Carbon; D043364:Endo-1,4-beta Xylanases