Table II. Mucin O-glycans identified from chicken caecum, small intestine, and large intestine.

CMSI, chicken mucin small intestine; CMLI, chicken mucin large intestine. O-glycans identified from human intestinal track as reported by Robbe et al. are also indicated with a ü where structural detail is provided or a ª where only a corresponding glycan composition is reported (28). All ions are [M-H]⁻ unless otherwise indicated as [M-2H]^2-. Monosaccharides linked to the 6-position of the reducing end HexNAcol are specified in bold and linkage positions are shown. Molecular ions 1469.3, 1615.3, 1680.5, 1826.3, indicated with an *, were also observed as [M-2H]^2- ions; 734.3, 807.3, 839.8 and 912.8. The percentage relative abundance of each structure is shown (in bold) as a ratio of the measured intensity (monoisotopic peak including the two adjacent isotopic peaks) of each ion to the sum of all measured intensities. The second value (in parentheses) is the relative abundance of each structure within type [i.e. ratio of measured intensity to the sum of intensities within type (neutral, sialylated, sulphated, sialylated-sulphated)]. Intensity distribution of structural isomers was not discernible for the following glycans; m/z 870.27 (caecum, CMSI, CMLI), m/z 1389.42 (CMSI, CMLI), m/z 1405.33 (CMLI). Structures where sulphate residues are not specifically assigned are designated “(SO3⁻)+” to denote the presence of sulphate. Fuc, fucose; Hex, hexose (i.e. galactose); HexNAc, N-acetylhexosamine (i.e. N-acetylglucosamine or N-acetylgalactosamine); HexNAcol, reduced N-acetylhexosaimine (i.e. N-acetylgalactosaminol); Neu5Gc, N-glycolylneuraminic acid; Neu5NAc, N-acetylneuraminic acid; SO₃⁻, sulphate.