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Fast Proton Exchange in Histidine: Measurement of Rate Constants through Indirect Detection by NMR Spectroscopy
Author(s) -
Sehgal Akansha Ashvani,
Duma Luminita,
Bodenhausen Geoffrey,
Pelupessy Philippe
Publication year - 2014
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201304992
Subject(s) - imidazole , chemistry , histidine , proton , reaction rate constant , spectroscopy , aqueous solution , nuclear magnetic resonance spectroscopy , analytical chemistry (journal) , crystallography , stereochemistry , kinetics , enzyme , organic chemistry , physics , quantum mechanics
Owing to its imidazole side chain, histidine participates in various processes such as enzyme catalysis, pH regulation, metal binding, and phosphorylation. The determination of exchange rates of labile protons for such a system is important for understanding its functions. However, these rates are too fast to be measured directly in an aqueous solution by using NMR spectroscopy. We have obtained the exchange rates of the NH 3 + amino protons and the labile NH ε2 and NH δ1 protons of the imidazole ring by indirect detection through nitrogen‐15 as a function of temperature (272 K< T <293 K) and pH (1.3