Chemoenzymatic preparation of dermatan sulfate oligosaccharides as arylsulfatase B and alpha-L-iduronidase substrates

Dermatan sulfate was partially depolymerized with chondroitin ABC lyase to obtain an oligosaccharide mixture from which an unsaturated disulfated tetr asaccharide was purified and characterized using nuclear magnetic resonance spectroscopy and electrospray ionization mass spectrometry. Chemical remov al of the unsaturated uronate residue with mercuric acetate, followed by de -4-O-sulfation with arylsulfatase B (N-acetylgalactosamine 4-sulfatase) and N- acetylhexo-saminidase catalyzed removal of the 2-acetamido-2-deoxy-D-ga lactospyranosyl residue at the non-reducing end afforded a monosulfated dis accharide of the structure alpha -L-idopyranosyluronic acid (1-->3)-alpha,b eta -D-2-acetamido-2-deoxy-4-O-sulfo galactopyranose. This monosulfated dis accharide serves as a substrate for mammalian alpha -L-iduronidase as demon strated using fluorophore assisted carbohydrate electrophoresis.