Unconventional Zwitterionic State of L-Cysteine
Författare
Summary, in English
We report the signature of an unconventional zwitterion in thick (>40 angstrom) L-cysteine films grown at low temperature (100 K) by means of sublimation in ultrahigh vacuum. Using X-ray photoelectron spectroscopy (XPS) we find that protonated amino groups (57%) are less prevalent than in films grown at higher temperatures. A large majority of the protonated amino groups receive the hydrogen through deprotonation of the thiol group (45%) and, in contrast, only a small fraction of the carboxylic groups (13%) is deprotonated. This shows, for the first time, the unconventional zwitterion to be the dominant species in L-cysteine. We believe the unusual growth parameters are responsible for this novel observation.
Avdelning/ar
Publiceringsår
2011
Språk
Engelska
Sidor
1677-1681
Publikation/Tidskrift/Serie
The Journal of Physical Chemistry Letters
Volym
2
Issue
14
Dokumenttyp
Artikel i tidskrift
Förlag
The American Chemical Society (ACS)
Ämne
- Physical Sciences
- Atom and Molecular Physics and Optics
- Natural Sciences
Status
Published
ISBN/ISSN/Övrigt
- ISSN: 1948-7185