Figure 5.

MALDI TOF mass spectra of the PtrGT43B/C-catalyzed reaction products. Microsomes from PtrGT43B/C-coexpressing transgenic cell lines (PtrGT43B/C-2, -4 and -9) and poplar stems were incubated with UDP-Xyl and the Xyl₄-AA acceptor, and the reaction products were detected by MALDI TOF MS according to Lee et al.¹⁶ The spectra of the reaction products show that in addition to the Xyl₄-AA acceptor, a series of ions with a mass increment of 132 D corresponding to one xylosyl residue were present. These ions correspond to AA-labeled oligosaccharides [Xyl_n-AA + Na]⁺ composed of 4 to 10 Xyl residues.