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17O-NMR. of Enriched Acetic Acid, Glycine, Glutamic Acid and Aspartic Acid in Aqueous Solution. I. Chemical Shift Studies

✍ Scribed by Ioannis P. Gerothanassis; Roger Hunston; Jürgen Lauterwein

Publisher
John Wiley and Sons
Year
1982
Tongue
German
Weight
576 KB
Volume
65
Category
Article
ISSN
0018-019X

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✦ Synopsis

Abstract

The ^17^O‐NMR. chemical shifts of the enriched amino acids glycine, aspartic acid and glutamic acid were measured in aqueous solution as a function of pH. High magnetic fields are necessary to resolve the α, β‐ and α, γ‐carboxyl resonances of aspartic acid and glutamic acid, respectively. The chemical shifts of acetic acid were measured for comparative reasons. Ionization constants and titration shifts were obtained by nonlinear least‐squares fits to one‐proton titration curves. The average excitation energy approximation is discussed in terms of the observed changes in ^17^O‐shielding on deprotonation. No intramolecular association between the α‐amino group and the α‐carboxyl group in the zwitterionic form is required to explain the high‐frequency shift of the carboxylate ion. Also no indication of an intramolecular association between the α‐amino group and the side‐chain carboxyl groups of aspartic acid or glutamic acid was found.

📜 SIMILAR VOLUMES

17O-NMR. of Enriched Acetic Acid, Glycin
17O-NMR. of Enriched Acetic Acid, Glycine, Glutamic Acid and Aspartic Acid in Aqueous Solution. II. Relaxation Studies
✍ Ioannis P. Gerothanassis; Roger Hunston; Jürgen Laulenvein 📂 Article 📅 1982 🏛 John Wiley and Sons 🌐 German ⚖ 607 KB

## Abstract The ^17^O‐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 ^17^O‐NMR. line‐width maxima of glycine at pH≈︁11 and acetic acid at pH≈︁5 are shown to arise

17O NMR chemical shifts of the twenty pr
17O NMR chemical shifts of the twenty protein amino acids in aqueous solution
✍ Ioannis P. Gerothanassis; Roger N. Hunston; JÜRgen Lauterwein 📂 Article 📅 1985 🏛 John Wiley and Sons 🌐 English ⚖ 882 KB

## Abstract The ^17^O chemical shifts of the α‐carboxyl groups of the protein amino acids, including 4‐hydroxyproline, sarcosine and __N,N__‐dimethylglycine, were measured at 40°C in aqueous solution at variable pH (^17^O enrichment 10 atom‐%). The chemical shifts of the amino acids were found to b