Rapid Mass Spectrometric Analysis of a Novel Fucoidan, Extracted from the Brown Alga Coccophora langsdorfii

The novel highly sulfated (35%) fucoidan fraction Cf2, which contained, along with fucose, galactose and traces of xylose and uronic acids was purified from the brown alga Coccophora langsdorfii. Its structural features were predominantly determined (in comparison with fragments of known structure) by a rapid mass spectrometric investigation of the low-molecular-weight fragments, obtained by mild (5mg/mL) and exhaustive (maximal concentration) autohydrolysis. Tandem matrix-assisted laser desorption/ionization mass spectra (MALDI-TOF/TOFMS) of fucooligosaccharides with even degree of polymerization (DP), obtained by mild autohydrolysis, were the same as that observed for fucoidan from Fucus evanescens, which have a backbone of alternating (1 -> 3)- and (1 -> 4) linked sulfated at C-2 and sometimes at C-4 of 3-linked alpha-L-Fucp residues. Fragmentation patterns of oligosaccharides with odd DP indicated sulfation at C-2 and atC-4 of (1 -> 3) linked alpha-L-Fucp residues on the reducing terminus. Minor sulfation at C-3 was also suggested. The exhaustive autohydrolysis allowed us to observe the mixed oligosaccharides, built up of fucose/xylose and fucose/galactose. Xylose residues were found to occupy both the reducing and nonreducing termini of FucXyl disaccharides. Nonreducing galactose residues as part of GalFuc disaccharides were found to be linked, possibly, by 2-type of linkage to fucose residues and were found to be sulfated, most likely, at position C-2.