Investigation of fucoidanase by FTIR spectra

Fucoidanase was isolated and purified from marine fungus LD8 by solid state fermentation,extraction with citric acid buffer,acetone precipitatation and column chromatography on Sephadex G-100.A single band on PAGE shows that pretty pure fucoidanase has been obtained.FT-IR spectra and its derivation,self-deconvolution and curve-fitting methods were used to analyze the secondary structure of the fucoidanase.Composite bands of the amide Ⅰ and amide Ⅲ were studied by using Fourier self-deconvolution(FSD) with an enhancement factor of K=2.2 and a half width of 20.2 cm-1.The relative average fractions of α-helix,β-sheet,random coil,β-turn are 11.5%,58.6%,14.5% and 15.9%,respectively,according to amide Ⅰ region,while the content of α-helix is 12%,β-sheet 57.3%,random coil 14.5%,and β-turn 16.3% on amide Ⅲ region.In other words,both the conclusions were exactly consistent.All the above results show that β-sheet was the dominant component,which is about 58%,and that β-turn is about 15%,random coil 15%,and α-helix 12% at room temperature.