Investigation of the Amino Acids Glycine, Proline, and Methionine by Photoemission Spectroscopy

Abstract

The valence and core level photoelectron spectra of glycine, proline, and methionine in the gas phase have been investigated by VUV and soft X-ray radiation. The outer valence band photoemission spectra are similar to previously reported He I spectra, although relative peak intensities are different due to the different photon energy. We extended the spectral range to include the inner valence region. The carbon, nitrogen, and oxygen 1s as well as the sulfur 2p core level spectra of these amino acids have been measured and the states identified. Valence band spectra of proline have been recorded as a function of temperature, and they provide information about the relative populations of the lowest energy conformers.

Photodissociation of protonated leucine-enkephalin in the VUV range of 8–40 eV

“…32 But this fragment ion also is the dominant peak in dissociative photoionization of neutral gas phase tyrosine. 43,44 Loss of a charged aromatic side chain, i.e., breaking of the C α -C β bond for a neutral tryptophan-gly n peptide has also been observed. 45 Below the ionization thresh- + .…”

“…43) is dominated by intense peaks due to valence electrons at binding energies between 10 and 19 eV, with the lowest three being due to the N lone pair n N (HOMO), the hydroxyl O lone pair n O and the bonding carbonyl orbital π CO . The weaker peaks at higher binding energies are due to single electron ionizations.…”

“…7(d)]. The above mentioned photoelectron data 43,44 for the different amino acids are displayed for comparison [see Figs. 7(a)-7(c)].…”

Photoelectron spectra and structures of three cyclic dipeptides: PhePhe, TyrPro, and HisGly

“…The aim of this study is to determine the intrinsic structure-property relationship of a number of cyclic dipeptides, using the experimental [11][12][13][14] and theoretical methods [15][16][17] previously applied to modelling both valence and inner-shell electronic states of biomolecules.…”

Structures of Cycloserine and 2-Oxazolidinone Probed by X-ray Photoelectron Spectroscopy: Theory and Experiment

“…[25][26][27][28] The total resolution of the photons and analyzer was estimated to be 0.2, 0.32, 0.46, and 0.78 eV at photon energies of 100 (valence band), 382 (C 1s), 495 (N 1s), and 628 eV (O 1s), respectively. The compounds were supplied by Sigma Aldrich (purity > 98%) and used without further purification.…”