窄分子量分布低聚壳聚糖与HSA相互作用的荧光光谱研究

Fluorescence Study on the Interaction of Narrow Distribution Low Polymerization Degree Chitooligosaccharides and Human Serum Albumin

在室温近似生理酸度条件下,利用荧光光谱法,对不同聚合度(DP)的窄分子量分布低聚壳聚糖(CTS)与人血清白蛋白(HSA)的相互作用进行初步探讨。结果表明:向HSA溶液中加入六种不同DP窄分子量分布的CTS,HSA的相对荧光强度均发生了变化,表明均与HSA存在相互作用。进一步发现随着低聚窄分子量CTS的DP减小,与HSA相互结合作用有规律的逐步加强;然而,当DP减小到8以下时其结合作用又开始减弱,至氨基葡萄糖(CTS降解的最终产物单糖)时,相互作用几乎消失。这一结果表明链状壳聚糖分子与蛋白生物大分子之间的作用存在尺度效应,且当CTS的DP为8左右时与HSA的结合能力最强,DP的增大或减小都会导致相互作用减弱。

Chitosan （CTS）, a linear binary copolymer of （1→8）-linked 2-acetamido-2-deoxy-/？-D-glucopyranose （GlcNAc unit） and 2-amino-2-deoxy-β-Dglucopyranose （GlcNH2 unit）, is derived from chitin by alkaline deacetylation. In the present work, the narrow molecular weight distribution ehitooligosaccharides were prepared by degraded CTS with a microwave-assisted-cleavage method of metal-coordinating template-absorption catalytic oxidation. Under physiological pH conditions, the interaction of CTS and the narrow distribution chitooligosaceharides with Human serum albumin （HSA） was preliminarily explored by fluorescence spectra. Low molecular weight CTS in different concentration was added into HSA solution respectively, the absorptivity of the HSA solution decreased considerably. This phenomenon indicated that there was an interaction between these six different low molecular weight CTS with HSA, and the smaller the DP of the narrow distribution ehitooligosaccharides, the stronger the interaction with HSA. However, the interaction gradually failed in as the DP was less than eight. The interaction almost disappeared when using gtucosamine, the final product of degraded CTS, which revealed that there was a scale effect between chainlike CTS molecule and protein biomacromoleeule. The results suggest that the strongest interaction binding occurs in CTS with DP≈8. Whether the DP increases or decreases, the interaction will weaken.