FIGURE 3.

S2B is acetylated on the 6-deoxytalose. A, positive ion mode ESI mass spectra of native (N) and deacetylated (DA) biologically active S2B were compared and demonstrated a shift of approximately one acetyl group (42 atomic mass units) when comparing relevant peaks (i.e. m/z 1519 versus m/z 1477, and m/z 1553 versus m/z 1511). B, selected ions were subjected to undergo CAD. At a collision energy of 20 eV, product ions represented the protonated GPL ion with the sequential loss of sugar moieties.