title: Characterization of white wine mannoproteins.
abstract: Mannoproteins, Saccharomyces cerevisiae yeast polysaccharides, play a major role in wine processing and characteristics. A systematic characterization of these polymers in terms of chemical composition and molecular structure is addressed in this study. Mannoproteins were isolated from white wine through a sequence of operations that consisted of nanofiltration for concentration of macromolecules, polysaccharide precipitation with ethanol, and affinity chromatography on concanavalin A. The whole wine mannoproteins present a very broad molecular mass distribution with several populations. Two major populations with very different compositions were separated by size exclusion chromatography. The mannoproteins with higher molecular mass are a mannose homopolymer containing 10.3% protein. The mannoproteins with lower molecular mass consisted of 87.5% of mannose and some other residues and a protein content of 2.5%. The highest molecular weight mannoprotein structure was examined by (1)H and (13)C NMR spectroscopic techniques such as 1-D TOCSY, 2-D COSY, and 2-D HMQC.
mesh_terms: D011232:Chemical Precipitation; D002846:Chromatography, Affinity; D002850:Chromatography, Gel; D003208:Concanavalin A; D000431:Ethanol; D005374:Filtration; D009682:Magnetic Resonance Spectroscopy; D008358:Mannose / Q000032:analysis; D008562:Membrane Glycoproteins / Q000032:analysis* / Q000302:isolation & purification; D008970:Molecular Weight; D011134:Polysaccharides / Q000302:isolation & purification; D014920:Wine / Q000032:analysis*
chemical_list: D008562:Membrane Glycoproteins; D011134:Polysaccharides; C025363:mannoproteins; D003208:Concanavalin A; D000431:Ethanol; D008358:Mannose