title: Variations of pH as an additional tool in the analysis of crowded NMR spectra of fucosylated chondroitin sulfates.
abstract: The influence of pH variation on chemical shift values in NMR spectra of fucosylated chondroitin sulfates was studied using polysaccharides isolated from three sea cucumber species Apostichopus japonicus, Actinopyga mauritiana and Cucumaria japonica. The signals of glucuronic acid residues were found to be the most sensitive to pH changes in comparison to the chemical shifts of the sulfated galactosamine and fucosyl units, most of which were altered insignificantly. It was shown that in the presence of imidazole-HCl buffer (pH 7.2) NMR spectra of the polysaccharides from A. japonicus and A. mauritiana were sufficiently resolved, whereas under acidic conditions their (1)H NMR spectra were complicated by overlapping of H-1 signals of GlcA and GalNAc. In the case of polysaccharide from C. japonica bearing 3-O-fucosylated and 3-O-sulfated glucuronic acid residues in the backbone, acidification of the medium led to separation of H-1 signals of GlcA3S and GalNAc. Therefore, the combination of data obtained at different pH values may be useful for interpretation of overcrowded spectra of fucosylated chondroitin sulfates.
authors.affiliation: N.D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Leninsky prospect 47, Moscow 119991, Russia. Electronic address: ustnad@gmail.com.
authors.forename: Nadezhda E
authors.initials: NE
authors.lastname: Ustyuzhanina
authors.affiliation: N.D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Leninsky prospect 47, Moscow 119991, Russia.
authors.forename: Andrey S
authors.initials: AS
authors.lastname: Dmitrenok
authors.affiliation: N.D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Leninsky prospect 47, Moscow 119991, Russia.
authors.forename: Maria I
authors.initials: MI
authors.lastname: Bilan
authors.affiliation: N.D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Leninsky prospect 47, Moscow 119991, Russia.
authors.forename: Alexander S
authors.initials: AS
authors.lastname: Shashkov
authors.affiliation: N.D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Leninsky prospect 47, Moscow 119991, Russia.
authors.forename: Alexey G
authors.initials: AG
authors.lastname: Gerbst
authors.affiliation: N.D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Leninsky prospect 47, Moscow 119991, Russia.
authors.forename: Anatolii I
authors.initials: AI
authors.lastname: Usov
authors.affiliation: N.D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Leninsky prospect 47, Moscow 119991, Russia.
authors.forename: Nikolay E
authors.initials: NE
authors.lastname: Nifantiev
mesh_terms: D000818:Animals; D002809:Chondroitin Sulfates / Q000737:chemistry* / Q000302:isolation & purification; D006863:Hydrogen-Ion Concentration; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D012616:Sea Cucumbers / Q000737:chemistry
chemical_list: C517150:fucosylated chondroitin sulfate; D002809:Chondroitin Sulfates
keywords: Actinopyga mauritiana; Apostichopus japonicus; Cucumaria japonica; Fucosylated chondroitin sulfate; NMR; Sea cucumber