Determination of acid dissociation constants of histidine‐containing peptides by proton magnetic resonance spectroscopy
- 1 March 1983
- journal article
- research article
- Published by Wiley in Magnetic Resonance in Chemistry
- Vol. 21 (3) , 208-213
- https://doi.org/10.1002/omr.1270210315
Abstract
The acid dissociation constant of the imidazolium ring of the decapeptide luliberin has been determined by 1H NMR‐followed titration in D2O. The normal procedure for the analysis of the titration curve, i.e. direct use of the Henderson‐Haselbalch equation, is still applicable in this case, but for more complex peptides a modified calculation procedure is proposed. Results obtained when both methods were applied to luliberin are compared. The influence of D2O when used as the solvent in this type of determination has been studied using Nα‐acetyl‐L‐histidine methyl ester as a model compound. The difference between the acid dissociation constant of this molecule determined in H2O and in D2O implies that a correction of −.25 unit is needed for those pKa values calculated by plotting the chemical shifts in D2O vs the apparent pH meter readings. The pKa found for Nα‐acetyl‐L‐histidine methyl ester, 6.30 ± 0.04, can be taken as a standard value for histidine‐containing peptides.Keywords
This publication has 17 references indexed in Scilit:
- Determination of the microscopic and macroscopic acid dissociation constants of glycyl-L-histidyl-L-lysine and related histidine peptidesBiochemistry, 1977
- Conformational analysis of amino acids and peptides using specific isotope substitution. II. Conformation of serine, tyrosine, phenylalanine, aspartic acid, asparagine, and aspartic acid .beta.-methyl ester in various ionization statesJournal of the American Chemical Society, 1975
- Photochemistry of diazonium salts. III. New and facile synthesis of 4-fluorimidazolesThe Journal of Organic Chemistry, 1973
- Orientation restrictions of the peptide hormone, thyrotropin-releasing factor, due to intramolecular hydrogen bondingBiochemistry, 1972
- Nuclear magnetic resonance studies of human carbonic anhydrase B. histidine residuesBiochemistry, 1971
- Nuclear magnetic resonance studies of the structure and binding sites of enzymes: XIV. Inhibitor binding to staphylococcal nucleaseJournal of Molecular Biology, 1970
- Transesterification with an anion-exchange resinThe Journal of Organic Chemistry, 1969
- Nuclear magnetic resonance studies of the structure and binding sites of enzymes. VII. Solvent and temperature effects on the ionization of histidine residues of ribonucleaseBiochemistry, 1969
- Analysis of Proton Magnetic Resonance Spectra of Cysteine and Histidine and Derivatives. Conformational Equilibria1Journal of the American Chemical Society, 1965
- Nuclear magnetic resonance study of some α-amino acids—II. Rotational isomerismSpectrochimica Acta, 1964