PHOTOLABILE, SPACER-MODIFIED OLIGOSACCHARIDES FOR REGIOSELECTIVE CHEMICAL MODIFICATION AND PROBING OF RECEPTOR-BINDING SITES

During the past decade, biochemistry has undergone a gradual development from investigations of covalent molecular transformations, which occur in metabolism for instance to those of noncovalent molecular interactions, which can be summarized under the heading ''recognition phenomena''. The last, unsolved basic problems in molecular biology fall into this category. Organic chemistry, which is almost exclusively preoccupied with the making and breaking of covalent bonds, has, at least in part, developed into an auxiliary science for biology. Numerous examples exist where naturally occurring compounds have been modified synthetically in order to study changes induced in a biological system, and to compare them with the natural processes. One aim, which is the topic of this chapter, is to ''freeze'' reversible receptor ligand interactions by covalently linking the interacting molecules.