ALL-TRANSGLYCOLYTIC SYNTHESIS AND CHARACTERIZATION OF GALACTOSYL(BETA-1-4)XYLOSYL-P-NITROPHENYL(BETA-1-, AN OLIGOSACCHARIDE DERIVATIVE RELATED TO GLYCOSAMINOGLYCAN BIOSYNTHESIS

beta-D-Xylopyranosides, such as p-nitrophenyl-beta-D-xylopyranoside (X yl-Np) or 4-methylumbelliferyl-beta-D-xylopyranoside (Xyl-MeUmb), when added to the culture medium of human skin fibroblasts have previously been shown to produce some Np- or MeUmb-oligosaccharides related to t he regulation of glycosaminoglycan biosynthesis. Among these oligosacc haride derivatives, we synthesized the trisaccharide derivative NeuAc( a2-3)Gal(beta 1-4)Xyl-Np(beta 1- as a potential inhibitor of human ski n fibroblast glycosaminoglycan biosynthesis. This synthesis was achiev ed by sequential use of transglycosylating activities of Escherichia c oli beta-galactosidase and Trypanosoma cruzi trans-sialidase. The stru cture of the oligosaccharide obtained was determined by HPLC, ion-spra y mass spectrometry, and NMR.