Enzymic synthesis of 3′-O- and 6′-O-N-acetylglucosaminyl-N-acetyllactosaminide glycosides catalyzed by β-N-acetyl-D-hexosaminidase from Nocardia orientalis

Abstract β - N -acetyl-D-hexosaminidase from Nocardia orientalis catalyzed the synthesis of β -D-GlcNAc-(1→3)- β -D-Gal-(1→4)- β -D-GlcNAc-OC 6 H 4 NO 2 - p ( 1 ) and β -D-GlcNAc-(1→6)- β -D-Gal-(1→4)- β -D-GlcNAc-OC 6 H 4 NO 2 - p ( 2 ) with its isomer β -D-Gal-(1→4)-[ β -D-GlcNAc-(1→6)]- β -D-GlcNAc-OC 6 H 4 NO 2 - p ( 3 ) through N -acetylglucosaminyl transfer from N -, N ′-diacetylchitobiose to p -nitrophenyl β - N -acetyllactosaminide. The enzyme formed a mixture of trisaccharides 1 , 2 , and 3 in a ratio of 11 : 33 : 56. In the case, when an inclusion complex of p -nitrophenyl β - N -acetyllactosaminide with α -CD was used, compounds 1 , 2 , and 3 were formed in a molar ratio of 24 : 63 : 13. The regioselectivity of glycosidase-catalyzed formation of the trisaccharide glycosides was substantially changed. It resulted not only in a significant increase of the proportion of the desired compounds 1 and 2 but also in the substantial increase of the overall yield of transfer products.