title: Existence of hydroxylated MWCNTs demotes the catalysis effect of amylases against starch degradation.
abstract: Possible interaction between amylase and Multi Walled Carbon Nanotubes (MWCNTs) has been elucidated with spectroscopic methods. Hyperchromism of the UV-visible spectra of amylase-CNT conjugates suggested ground state complex formation between them. On contrary, the decreasing fluorescence emission spectra revealed the fate of quenching mechanism to be static. Stoke shift observed from the synchronous and 3D spectra suggested the possibilities of disturbances to the aromatic micro-environment of amylases by OH-MWCNTS. FTIR and FT-Raman spectra showed alteration in the amide I band, that corresponds to their effect on alpha-helical structures. Loss of alpha-helical structures and alteration in the dichroic band again revealed possible conformational change and effect towards the stability of polypeptide backbone structures. In addition, the shift observed in the SPR band and FTIR peaks of CNTs-amylase conjugates suggested possible alteration in their optical and structural properties. On the functional aspect, amylase activity on starch degradation and hydrolysis were found to be decreased in the presence of CNTs.
authors.affiliation: Centre for Nanobiotechnology, VIT University, Vellore 632014, Tamil Nadu, India.
authors.forename: Gajalakshmi
authors.initials: G
authors.lastname: Sekar
authors.affiliation: School of Advanced Sciences, VIT University, Vellore 632014, Tamil Nadu, India.
authors.forename: Amaravathy
authors.initials: A
authors.lastname: Sivakumar
authors.affiliation: Centre for Nanobiotechnology, VIT University, Vellore 632014, Tamil Nadu, India.
authors.forename: Amitava
authors.initials: A
authors.lastname: Mukherjee
authors.affiliation: Centre for Nanobiotechnology, VIT University, Vellore 632014, Tamil Nadu, India. Electronic address: nchandra40@hotmail.com.
authors.forename: Natarajan
authors.initials: N
authors.lastname: Chandrasekaran
mesh_terms: D000681:Amylases / Q000737:chemistry* / Q000378:metabolism*; D000818:Animals; D001412:Bacillus subtilis / Q000201:enzymology; D055162:Biocatalysis; D004800:Enzymes, Immobilized / Q000737:chemistry / Q000378:metabolism; D006900:Hydroxylation; D037742:Nanotubes, Carbon / Q000737:chemistry*; D055620:Optical Phenomena; D013213:Starch / Q000737:chemistry*; D013552:Swine
chemical_list: D004800:Enzymes, Immobilized; D037742:Nanotubes, Carbon; D013213:Starch; D000681:Amylases
keywords: Amylase; Binding; Carbon nanotubes; Conformational changes; Spectroscopy