Oligosaccharides of human milk. Structural studies of two new octasaccharides, difucosyl derivatives of para-lacto-N-hexaose and para-lacto-N-neohexaose

Abstract

Two new octasaccharides were isolated from human milk of a nonsecretor Lewis a+b- individual. Structural studies by sequential enzymic degradation and by quantitative methylation analysis revealed that their structures were as follows: Galbeta1 leads to 3 (Fucalpha1 leads to 4) GlcNAcbeta1 leads to 3Galbeta1 leads to 4 (Fucalpha1 leads to 3) GlcNAcbeta1 leads to 3Galbeta1 leads to 4Glc, Galbeta1 leads to 4 (Fucalpha1 leads to 3) GlcNAcbeta1 leads to 3Galbeta1 leads to 4 (Fucalpha1 leads to 3) GlcNAcbeta1 leads to 3Galbeta1 leads to 4Glc. The core portions of these sugars, which are newly found linear hexasaccharides, are named para-lacto-N-hexaose and para-lacto-N-neohexaose, respectively.