Spectroscopic characteristics of the β-fructosyltransferase(EC2.4.1.9 FTS) from Aspergillus oryzae GX0011 was studied by ultraviolet absorbance spectrum,fluorescence spectrum and circular dichroism.The enzyme exhibited that the characteristic peaks of ultraviolet absorbance spectrum,of fluorescence emission spectrum were at 280nm and 343nm.In low concentration of ,the fluorescence quenching was in line with the Sterm-Volmer’s equation and the percentage of Trp residue reacted by was 0.72.By comparing the fluorescence spectra of FTS substrate-perturbation,it was implied that some inner Trp residues participated in catalysis and might be involved in the active site of the enzyme.Furthermore,the secondary structures of FTS were quantitatively determined by circular dichroism.The relative percentage content of each secondary structure were:25.1±0.8% α-helix,5.3±2.3% β-sheet,31.4±1.5%β-turn and 38.2±1.1% random coil respectively.
