【摘要】 通过海洋真菌LD8固态发酵获得岩藻多糖的粗蛋白,并进一步采用柠檬酸缓冲液浸提、丙酮沉淀和葡聚糖凝胶G-100层析,分离纯化至单一组分;利用傅里叶变换红外光谱(fourier transform infrared spec-troscopy,FTIR)及曲线拟合等技术研究了岩藻多糖酶的二级结构组成,增强因子为2·2,半峰宽为20·2cm-1;为提高分析测定的准确性,对酰胺Ⅰ带与酰胺Ⅲ带分别进行拟合归属。结果表明:根据酰胺Ⅰ带所获得的二级结构,α-螺旋占11·5%,β-折叠为58·6%,无规卷曲14·5%,β-转角15·9%;酰胺Ⅲ带所得二级结构,α-螺旋含12%,β-折叠含57·3%,无规卷曲含14·5%,β-转角含16·3%。因此可见,酰胺Ⅰ带与酰胺Ⅲ带所对二级结构的分析是十分吻合的。在室温下,岩藻多糖酶的二级结构以β-折叠的含量占优势,约占58%,β-转角和无规卷曲次之,各占15%左右,α-螺旋含量较低,仅占12%。更多还原

【Abstract】 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.更多还原