摘要
分别将Ca(Ⅱ)和Zn(Ⅱ)加入到壳聚糖溶液中,调节pH值使壳聚糖与金属配位.加入H2O2并升高温度对处于配位缔合状态的壳聚糖进行氧化降解,测定了降解产物寡糖的数均相对分子质量和相对分子质量分布.结果表明壳聚糖在与Ca和Zn配位的情况下,可被H2O2迅速降解;降解从大相对分子质量范围开始,降解产物寡糖相对分子质量分布较窄,且聚合度(DP数)越小,寡糖相对分子质量分布指数越小.同时对两者的降解产物进行了清除超氧阴离子自由基(O2-.)的研究,研究发现两者的降解产物均对O2-.有一定的清除作用,清除率随降解产物数均相对分子质量的减小而增大.但用完全降解产物氨基葡糖形成配合物时,清除作用几乎完全消失.
Complexes of chitosan with Ca（ Ⅱ ） or Zn（ Ⅱ ） were prepared by adding CaAc2 · H2O or ZnAc2 ·2H2O to chitosan solution. H2O2 was used to degrade chitosan-Ca（ Ⅱ ） and Zn（ Ⅱ ） complex, the molecular weight and the molecular weight distribution of degraded products were investigated after eliminating Ca（ Ⅱ ） or Zn（ Ⅱ ） ions through the cation exchange resin. The results suggested that the chitosan could be degraded rapidly as the temperature raised;the degradation started from chitosan with higher molecular weight, the molecular weight distribution of oligosaccharides was narrow. The index of molecular weight distribution changed with the degree of degradation, the smaller the DP was,the smaller the index was. Moreover, the scavenging effect on the superoxide radical （O2^-） and the inhibitory effect on peroxides were also investigated. The results showed that both chitosan-Ca（ Ⅱ ） and chitosan-Zn（ Ⅱ ） exhibited scavenging effect. The smaller of DP, the higher of eliminated rate could be reached. However,when chitosan was degraded to glucosamine, the scavenging effect of metal coordination almost disappeared.
出处
《分子科学学报》
CAS
CSCD
2006年第6期376-380,共5页
Journal of Molecular Science
基金
国家自然科学基金资助项目(20361003)
国家863引导性项目(2005AA0012401)
关键词
壳聚糖
配位催化氧化
控制降解
超氧阴离子自由基
抗氧化
chitosan
coordination
controlled degradation
superoxide radical （O2^-）
the scavenging effect
antioxidation
