title: Time-resolved photodissociation of singly protonated peptides with an arginine at the N-terminus: a statistical interpretation.
abstract: Time-evolution of product ion signals in ultraviolet photodissociation (UV-PD) of singly protonated peptides with an arginine at the N-terminus was investigated by using a tandem time-of-flight mass spectrometer equipped with a cell floated at high voltage. Observation of different time-evolution patterns for different product ion types--an apparently nonstatistical behavior--could be explained within the statistical framework by invoking consecutive formation of some product ions and broad internal energy distributions for precursor ions. a(n) + 1 and b(n) ions were taken as the primary product ions from this type of peptide ions. Spectral characteristics in post-source decay, UV-PD, and collisionally activated dissociation at low and high kinetic energies could be explained via rough statistical calculation of rate constants. Specifically, the striking characteristics in high-energy CAD and UV-PD--dominance of a(n) and d(n) formed via a(n) + 1--were not due to the peculiarity of the excitation processes themselves, but due to quenching of the b(n) channels caused by the presence of arginine.
authors: Department of Chemistry, Seoul National University, Seoul, Korea.
authors: So Hee
authors: SH
authors: Yoon
authors: Yeon Ji
authors: YJ
authors: Chung
authors: Myung Soo
authors: MS
authors: Kim
mesh_terms: D000465:Algorithms; D001120:Arginine / Q000737:chemistry* / Q000528:radiation effects; D003627:Data Interpretation, Statistical; D010449:Peptide Mapping / Q000379:methods*; D010455:Peptides / Q000737:chemistry* / Q000528:radiation effects; D010777:Photochemistry / Q000379:methods*; D011522:Protons; D012680:Sensitivity and Specificity; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods*
chemical_list: D010455:Peptides; D011522:Protons; D001120:Arginine