The metabolic and biochemical impact of glucose 6-sulfonate (sulfoquinovose), a dietary sugar, on carbohydrate metabolism
作者:Juliana L. Sacoman、Lauren N. Badish、Thomas D. Sharkey、Rawle I. Hollingsworth
DOI:10.1016/j.carres.2012.09.014
日期:2012.11
the metabolism of this sugar through three main carbohydrate processing pathways and how this could influence its biological activity. Using (13)C NMR spectroscopy and enzyme assays, we showed that glucose 6-sulfonate cannot enter the pentosephosphatepathway, hence decreasing pentose and nucleotide biosyntheses. In glycolysis, glucose 6-sulfonate only provides one pyruvate per monosaccharide molecule
Enantioselective synthesis of isotopically labelled L-α-amino acids preparation of 13C-, 18O-and 2H-labelled L-serines and L-threonines
作者:W. F. J. Karstens、H. J. F. F. Berger、E. R. Van Haren、J. Lugtenburg、J. Raap
DOI:10.1002/jlcr.2580361108
日期:1995.11
[3-18O]-L-serine, [3-13C]-L-serine, [3-18O]-L-threonine, [3,4-13C2]-L-threonine and [3-2H]-L-threonine are prepared from simple commercially available, isotopically enriched starting materials like H218O, [13C]-paraformaldehyde, [13C2]-acetaldehyde and [1-2H]-acetaldehyde. The introduction of the side chain is based on the reaction of the anion of the bislactimether of cyclo-(D-Val-Gly) with a suitable reagent. For serine this is isotopically labelled benzylchloromethylether, whereas for threonine labelled acetaldehyde is used in combination with chlorotitaniumtris[diethylamide], introducing both stereocentres in one single step. The isotopomers of serine and threonine are obtained on the gram scale in good yields and high enantiomeric and diasteriomeric excesses. New syntheses for [18O]-benzylalcohol and isotopically enriched benzylchloromethylether are reported. Following the presented synthetic scheme these amino acids can be labelled at any position or at any combination of positions.
Biosynthesis of the modified peptide antibiotic nosiheptide in Streptomyces actuosus
作者:David R. Houck、Li Chun. Chen、Paul J. Keller、John M. Beale、Heinz G. Floss
DOI:10.1021/ja00225a035
日期:1988.8
The biosynthesis of the highly modified thiopeptide antibiotic, nosiheptide (1), was studied by feeding radioactive and stable-isotope-labeled precursors to cultures of the producing organism, Streptomyces actuosus. The stableisotope enrichments and/or coupling patterns in the isolated 1 were analyzed by NMR spectroscopy using various 1D and 2D NMR techniques. The results complete the confirmation