SYNTHETIC GLYCOCONJUGATES .6. PREPARATION AND BIOCHEMICAL EVALUATION OF NOVEL CLUSTER-TYPE GLYCOPOLYMERS CONTAINING GAL BETA(1-]4)GLCNAC (N-ACETYLLACTOSAMINE) RESIDUE

A simple and facile method for the syntheses of cluster-type homopolymers from omega-(acrylamido)alkyl glycosides of N-acetyllactosamine [beta-D-Galp-(1-->4)-beta-n-GlcpNAc] is described. An efficient procedure for the preparation of poly[omega-(acrylamido)alkyl O-(beta-D-galactopyranosyl)-(1-->4)-2-acetamido-2-deoxy-beta-D-glucopyranoside] was established on the basis of radical polymerization of the novel glycosides in the presence of ammonium persulfate and N,N,N',N'-tetramethylethylenediamine. These synthetic cluster glycopolymers exhibited good solubility in water and had sugar densities much higher than the glycopolymers derived from known n-pentenyl glycosides. The association constants of Erythrina corallodendron lectin (ECorL) with these cluster glycopolymers were evaluated by measuring the changes in fluorescence intensity of fluorescent-labeled ECorL induced by the addition of the polymeric ligands. Addition of the cluster-type glycopolymers having different degrees of N-acetyllactosamine density to ECorL induced a significant decrease of the fluorescence intensity at 520 nm, and this phenomenon was used for the determination of binding constants between the glycopolymers and ECorL.