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Unconventional Zwitterionic State of L-Cysteine

Författare:
Publiceringsår: 2011
Språk: Engelska
Sidor: 1677-1681
Publikation/Tidskrift/Serie: Journal of Physical Chemistry Letters
Volym: 2
Nummer: 14
Dokumenttyp: Artikel
Förlag: American Chemical Society

Sammanfattning

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.

Disputation

Nyckelord

  • Physics and Astronomy

Övriga

Published
Yes
  • ISSN: 1948-7185

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