Guanidinium Group Remains Protonated in a Strongly Basic Arginine Solution [electronic resource].
- Washington, D.C. : United States. Dept. of Energy. Office of Basic Energy Sciences, 2017. and Oak Ridge, Tenn. : Distributed by the Office of Scientific and Technical Information, U.S. Dept. of Energy
- Physical Description:
- pages 1,503-1,506 : digital, PDF file
- Additional Creators:
- Lawrence Berkeley National Laboratory, United States. Department of Energy. Office of Basic Energy Sciences, National Science Foundation (U.S.), and United States. Department of Energy. Office of Scientific and Technical Information
- Restrictions on Access:
- Free-to-read Unrestricted online access
- Knowledge of the acid dissociation constant of an amino acid has very important ramifications in the biochemistry of proteins and lipid bilayers in aqueous environments because charge and proton transfer depend on its value. The acid dissociation constant for the guanidinium group in arginine has historically been posited as 12.5, but there is substantial variation in published values over the years. Recent experiments suggest that the dissociation constant for arginine is much higher than 12.5, which explains why the arginine guanidinium group retains its positive charge under all physiological conditions. Here, we use X-ray photoelectron spectroscopy to study unsupported, aqueous arginine nanoparticles. By varying the pH of the constituent solution, we provide evidence that the guanidinium group is protonated even in a very basic solution. By analyzing the energy shifts in the C and N X-ray photoelectron spectra, we establish a molecular level picture of how charge and proton transport in aqueous solutions of arginine occur.
- Published through SciTech Connect., 05/16/2017., "ark:/13030/qt7mn4t878", ChemPhysChem 18 12 ISSN 1439-4235 AM, and Bo Xu; Michael I. Jacobs; Oleg Kostko; Musahid Ahmed.
- Funding Information:
- AC02-05CH11231 and DGE‐1106400
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