FIGURE 4.
Anomeric regions of the 600-MHz proton NMR spectra (30 °C) of fractions 121:I, 121:II, and 121:III derived from the human embryonic stem cell line SA121. Samples (∼0.1 mg of each sample) were dissolved in dimethyl sulfoxide/D2O (98:2, v/v). Above the spectra the six different structures (1–6) that were identified are depicted, and anomeric resonances are labeled by Roman numerals. The presence of a triplet resonance due to unsaturated cis bonds in the non-hydroxy fatty acids (nFA) is indicated, as are the H4 and H5 resonances stemming from the sphingosine base.