Laser ion beam photodissociation studies of model amino acids and peptides
- Texas A and M Univ., College Station (USA)
Visible (458-514.5 nm) and uv (333-385 nm) photodissociation of the (M + H){sup +} ions of dinitrophenyl (DNP) derivatized amino acids and peptides is reported. Photoexcitation of the DNP peptides by a visible proton results in fragmentation of the peptide chain with little fragmentation within the chromophore. Conversely, uv photoexcitation of the DNP peptides results in fragmentation of the chromophore as well as the peptide chain, but loss of NO or NO{sub 2} (within the chromophore) often dominates the photofragment ion spectrum. These results are rationalized with particular emphasis on energy-selective dissociation channels of large ionic systems. DNP-leucine and DNP-isoleucine (M + H){sup +} can be differentiated on the basis of photodissociation reactions which yield distonic radical cations. The rate of dissociation of photoexcited ions of DNP peptides is shown to decrease with increasing molecular weight (degrees of freedom). Lastly, comparisons between photodissociation and collision-induced dissociation as a structural probe are presented. 55 refs., 8 figs., 3 tabs.
- DOE Contract Number:
- AS05-82ER13023
- OSTI ID:
- 5115513
- Journal Information:
- Journal of the American Chemical Society; (USA), Journal Name: Journal of the American Chemical Society; (USA) Vol. 111:4; ISSN 0002-7863; ISSN JACSA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
400500* -- Photochemistry
AMINO ACIDS
CARBOXYLIC ACIDS
CHEMISTRY
DATA
DISSOCIATION
ELECTROMAGNETIC RADIATION
EXPERIMENTAL DATA
INFORMATION
LASER RADIATION
MOLECULAR STRUCTURE
NUMERICAL DATA
ORGANIC ACIDS
ORGANIC COMPOUNDS
PEPTIDES
PHOTOCHEMISTRY
PROTEINS
RADIATIONS