Figure 3.

Evidence for the formation of hybrid-type N-glycans with bisecting LacNAc. Panel A demonstrates the effect of ¹³C₆-galactose transfer to Man5GnF⁶bi (BD₄-reduced) by either β3GalT or β4GalT, followed by mild mannosidase digestion (compounds 1, 2, and 3) and removal of the core fucose (peaks 4 and 5). Peaks 3 and 5 coelute with peaks 541c and 540b, respectively (Figure 4). Panels B to D show the positive mode CID spectra of peaks 1, 2, and 3 (MH⁺ = 1796.68). Cartoons are only given for some y and b ions with tentative selection of possible isomers. The red arrow denotes a product of internal re-arrangement.