Kinetics of gas-phase hydrogen/deuterium exchange and gas-phase structure of protonated phenylalanine, proline, tyrosine and tryptophan

Rožman, Marko; Kazazić, Saša; Klasinc, Leo; Srzić, Dunja (2003) Kinetics of gas-phase hydrogen/deuterium exchange and gas-phase structure of protonated phenylalanine, proline, tyrosine and tryptophan. Rapid Communications in Mass Spectrometry, 17 (24). pp. 2769-2772. ISSN 0951-4198

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Abstract

Site-specific rate constants for the gas-phase hydrogen/deuterium (H/D) exchange of four, three, five and five hydrogen atoms in protonated phenylalanine (Phe), proline (Pro), tyrosine (Tyr) and tryptophan (Trp), respectively, were determined from matrix-assisted laser desorption/ionization Fourier transform ion cyclotron resonance mass spectrometry (MALDI-FTICRMS) experiments with D2O, D2S, and CH3OD as deuterating agents. No H/D exchange was observed with D2S. For exchange with both CD3OD and D2O, which is about ten times slower in the latter, results indicate for all compounds protonation of the -amino group in agreement with theoretical results. Also, with both reagents, all compounds exchange at the COOH site more than ten times faster than at the protonation site, with OH and NH sites of Tyr and Trp, respectively, exchanging slowest. The observation of H/D exchange despite the high differences in proton affinities between the amino acids and deuterating agent exceeding 200 kJ mol-1 is in agreement with lowering of the barrier for proton transfer through hydrogen bonding proposed by Lebrilla and coworkers.

Item Type:	Article
Additional Information:	"This is the peer reviewed version of the following article: Rožman, Marko; Kazazić, Saša; Klasinc, Leo; Srzić, Dunja (2003) Kinetics of gas-phase hydrogen/deuterium exchange and gas-phase structure of protonated phenylalanine, proline, tyrosine and tryptophan. Rapid Communications in Mass Spectrometry, 17 (24). pp. 2769-2772, which has been published in final form at http://onlinelibrary.wiley.com/doi/10.1002/rcm.1261/full . This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving."
Uncontrolled Keywords:	hydrogen/deuterium exchange; mass spectrometry
Subjects:	NATURAL SCIENCES > Chemistry
Divisions:	Division of Physical Chemistry
Depositing User:	Kristina Ciglar
Date Deposited:	20 Jan 2017 16:39
URI:	http://fulir.irb.hr/id/eprint/3345
DOI:	10.1002/rcm.1261

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