ISSN:
0018-019X
Keywords:
Chemistry
;
Organic Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
The 17O-NMR. line widths of the enriched amino acids glycine, aspartic acid, glutamic acid and, for comparative reasons, acetic acid were measured in aqueous solution between pH 1 and 14. The 17O-NMR. line-width maxima of glycine at pH≍11 and acetic acid at pH≍5 are shown to arise from traces of paramagnetic metal ions. The increase in line width in case of glycine on going from the zwitterion 10 the cataion is attributed to an increase in the 17O-quadrupole coupling constant. No evidence for an intermolecular or intramolecular association of glycine in the zwitterionic form was found. When the paramagnetic impurities were eliminated by addition of EDTA, both the longitudinal and transverse relaxation times remained unchanged on deprotonation of the amino group. The overlapping of the α, β- and α, γ-carboxyl resonances of aspartic and glutamic acid, respectively, created difficulties for their line-width analysis.
Additional Material:
2 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/hlca.19820650613
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