Enzymic synthesis of the trisaccharide core region of the carbohydrate chain ofN-glycoprotein

Transmannosylation from mannotriose (Manß1-4Manß1-4Man) to the 4-position at the nonreducing end N-acetylglucosaminyl residue ofN,N'-diacetylchitobiose was regioselectively induced through the use of ß-d-mannanase fromAspergillus niger. The enzyme formed the trisaccharide Manß1-4GlcNAcß1-4GlcNAc (3.7% of the enzyme-catalysed net decrease ofN,N'-diacetylchitobiose) from mannotriose as a donor andN,N'-diacetylchitobiose as an acceptor. Mannobiose (Manß1-4Man) was also shown to be useful as a donor substrate for the desired trisaccharide synthesis.