Characterization of methyl sugars, 3-deoxysugars and methyl deoxysugars in marine high molecular weight dissolved organic matter
Repeta, Daniel J.
Johnson, Carl G.
MetadataShow full item record
Nuclear magnetic resonance spectroscopy of marine high molecular weight dissolved organic matter (HMWDOM) in surface waters show that >50% of the carbon is a compositionally well-defined family of acylated-polysaccharides that are conserved across ocean basins. However, acid hydrolysis of HMWDOM followed by chromatographic analyses recover only 10-20% of the carbon as neutral, amino, and acidic sugars. Most carbohydrate in HMWDOM therefore remains uncharacterized. Here we use acid hydrolysis followed by Ag+ and Pb2+ cation exchange chromatography to separate HMWDOM hydrolysis products for characterization by 1-D and 2-D NMR spectroscopy. In addition to neutral sugars identified in past studies, we find 3-Omethylglucose, 3-O-methylrhamnose, 2-O-methylrhamnose and 2-O-methylfucose. We also find 3-deoxysugars to be present, although their complete structures could not be determined. Methyl sugars are widely distributed in plant and bacterial structural carbohydrates, such as cell wall polysaccharides, and their presence in HMWDOM suggests that structural carbohydrates may contribute to DOM in surface seawater. We find most HMWDOM carbohydrate is not depolymerized by acid hydrolysis, and that the nonhydrolyzable component includes 6-deoxysugars.
Author Posting. © Elsevier B.V., 2007. This is the author's version of the work. It is posted here by permission of Elsevier B.V. for personal use, not for redistribution. The definitive version was published in Organic Geochemistry 38 (2007): 884-896, doi:10.1016/j.orggeochem.2007.02.005.
Showing items related by title, author, creator and subject.
Sloboda, Roger D.; Howard, Louisa (2009-04-28)Post-translational protein modification occurs extensively in eukaryotic flagella. Here we examine protein methylation, a protein modification that has only recently been reported to occur in flagella (Schneider et al. ...
Pangallo, Kristin C. (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 2009-09)Halogenated 1’-methyl-1,2’-bipyrroles (MBPs) are a distinctive class of marine organic compounds. They are naturally produced, they have a unique carbon structure, they are highly halogenated, and they bioaccumulate in ...
Hammerschmidt, Chad R.; Lamborg, Carl H.; Fitzgerald, William F. (2006-10-17)The source of monomethylmercury (MMHg) in wet deposition is unknown. Volatilization of gaseous MMHg, evasion and demethylation of dimethylmercury, and methylation of Hg0 have been either proposed or tested unsuccessfully ...