CHEMOENZYMATIC SYNTHESIS OF A GLYCOPOLYMER CARRYING CLUSTERED-N-ACETYL-BETA-LACTOSAMINE MOIETIES

A polyacrylamide derivative having a beta-linked N-acetyllactosamine moiety, a major component of oligosaccharide chains of glycoproteins, on each repeating unit was synthesized via a chemo-enzymatic process. p-Nitrophenyl N-acetyl-beta-lactosaminide was prepared by an one-step enzymatic synthesis, using a beta-galactosidase as catalyst, from p-nitrophenyl N-acetyl-beta-D-glucosaminide as the glycosyl acceptor and lactose as the glycosyl donor. The nitro group was reduced to an amino function, which was then allowed to react with either acryloyl chloride or acrylic acid. The resulting p-acryloylaminophenyl N-acetyt-beta-lactosaminide was polymerized with azobisisobutyronitrile as initiator in dimethyl sulfoxide to give a homdpolymer with a number-average molecular weight (($$$) over bar M(n)) of 3.2 x 10(5). High molecular-weight polymers carrying alpha-lactose, N-acetyl-beta-D-glucosamine, and alpha-D-glucopyranose were also synthesized as reference polymers in similar manners. Solution properties of these poly-p-acryloylaminophenyl derivatives are discussed on the basis of the hydrophilic-hydrophobic unit structures.