Table V.

ESI-MS protonated molecular ions of the oligosaccharides present in side chain B fractions generated by selective acid hydrolysis of RG-II from lycophytes, pteridophytes, and angiosperms

RG-II was isolated by SEC from the material solubilized from the lycophyte and pteridophyte walls by treatment with EPG. The purified RG-II was then treated for 24 h at 40°C with 0.1 m TFA to selectively hydrolyze the glycosidic bond of the apiosyl residue of side chain B. Side chain B fractions were isolated by SEC and analyzed by ESI-MS and ESI/MS-MS in the positive ion mode.

[M + H]+ Deduced Number of Glycosyl and O-Acetyl Residuesa Fragmentb Plant Sourcec
Api Rha Ara Gal AceA 2MeFuc 3MeRha O-Acetyl
1,056 1 2 1 1 1 1 0 0 1 Rw,At,Eh,Sk
1,070 1 1 1 1 1 1 1 0 2 Pn,Pb
1,098 1 2 1 1 1 1 0 1 1a Rw,At,Eh,Sk
1,112 1 1 1 1 1 1 1 1 2a Pn,Pb
1,140 1 2 1 1 1 1 0 2 1b Rw,At,Eh,Sk
1,154 1 1 1 1 1 1 1 2 2c Pn,Pb
1,188 1 2 2 1 1 1 0 0 3 Rw
1,202 1 3 1 1 1 1 0 0 4 Rw
1,216 1 2 1 1 1 1 1 0 5 Lt
1,230d 1 1 1 1 1 1 2 0 6 Pn,Pb
1,230d 1 2 2 1 1 1 0 1 3a Rw
1,244 1 3 1 1 1 1 0 1 4a Rw
1,258 1 2 1 1 1 1 1 1 5a Pb,Lt,Cte
1,272 1 1 1 1 1 1 2 1 6a Pn,Pb
1,286 1 3 1 1 1 1 0 2 4b Rw
1,300 1 2 1 1 1 1 1 2 5b Lt
1,314 1 1 1 1 1 1 2 2 6b Pn,Pb
1,334 1 3 2 1 1 1 0 0 7 Rw
1,376 1 3 2 1 1 1 0 1 7a Rw
1,418 1 3 2 1 1 1 0 2 7b Rw
  • aThe number of glycosyl and O-acetyl residues was determined from the [M + H]+ ion. The glycosyl residue compositions of the oligosaccharides were determined by GC/EI-MS analyses of the alditol acetate derivatives. bThe deduced glycosyl sequences of oligosaccharide fragments 1, 5, 6, and 7 are shown in Figure 6. cAt, Arabidopsis; Ct, C. thalictroides; Eh, E. hyemale; Lt, L. tristachyum; Pb, P. bifurcatum; Pn, P. nudum; Rw, red wine; Sk, S. kraussiana. d3a and 6 have the same molecular mass. Only P. nudum and P. bifurcatum RG-IIs contain 3-O-methyl rhamnosyl residues (see Table III). eFragment 5a generated from C. thalictroides RG-II was detected by negative ion ESI-MS.