Disaccharide composition of CS/DS from INS-1832/13 cells.A, XIC at m/z 458.06 corresponding to internal oligosaccharides carrying one sulfate group per disaccharide, Δdp2nSn (n = 1, 2, 3, …), displays the CS/DS di- and oligosaccharides generated after chondroitinase ABC depolymerization. The inset shows the relative abundance of the different CS/DS di- and tetrasaccharides as calculated using an automated search routine (mean ± SD). B and C, HCD-MS2 spectra of CS/DS disaccharides from INS-1832/13 cells after chondroitinase ABC depolymerization; the monosulfated disaccharide, Δdp2S1, displayed as the [M-H]– precursor ion at m/z 458.0598 at normalized collision energy (NCE) 80% corresponding to ΔHexAGalNAc4S (B), and the disulfated disaccharide, Δdp2S2, displayed as the [M-2H]2– precursor ion at m/z 268.5056 at NCE 70%, corresponding to ΔHexA2SGalNAc4S (C). Mass accuracies of precursor and fragment ions are found in supplemental Tables S1 and S2.