REDUCTIVE CLEAVAGE METHOD FOR GLYCAN STRUCTURAL ANALYSIS

点击翻译按钮获取中文摘要

The determination of structure of complex carbohydrates is an important problem in many areas of biomedical investigation because of their involvement in cellular recognition processes, their role as structural materials, and their presence as antigenic determinants in tumors, bacteria, fungi and viruses. Because of their structural complexity, no single method for establishing their structure is available. The myriad of chemical methodologies currently available are very laborious and ambiguous results are often obtained. We, therefore, began a program to develop a new method for the structural characterization of complex glycans that would overcome the difficulties associated with the current methodologies, and preliminary studies with glycans that contain neutral aldoses and ketoses have established that such a method has been developed. The structural method that forms the basis of this proposal is referred to as the "Reductive Cleavage Method" because its salient feature is the regiospecific reductive cleavage of all glycosidic bonds in a fully methylated polysaccharide. This method is substantially different from "methylation analysis", however, because 1) all linkage positions and ring forms in a polysaccharide are established simultaneously, and 2) conversion of the fully methylated polysaccharide to derivatives suitable for g.l.c.-m.s. analysis is accomplished in a one-pot reaction without intermediate transfers. Based upon the results obtained from our initial investigations, we feel that the Reductive Cleavage Method has the potential to serve as a general method for the structural characterization of all complex carbohydrates, and experiments designed to examine the feasibility of this approach form the basis of this proposal. The research proposed here also has as its objective the integration of the Reductive Cleavage Method and previously-developed methodologies into an overall, simplified scheme for complex carbohydrate structural analysis.