Chemical Kinetics Simulation Of Decomposition Mechanism Of The Single Protonated Arginine

Mass spectrometry has a wide range of applications in the field of life science research,especially in the field of protein identification,peptide identification by peptide mass information and collision-induced dissociation mass spectrometry.At present,many protein and polypeptide fragmentation pathways have been documented,but in addition to the known cleavage pathways in the sequence database,many disruption pathways have not been well understood and classified due to disruption in the process of division.Theoretical simulation methods are commonly used and have been proved to be helpful in understanding and interpreting experimental methods for mass spectrometry.The arginine studied in this article is an important part of many organisms in the body to identify and control processes,and is the most widely used amino acid in animal cells.In addition,a number of recent experiments have demonstrated that arginine residues can also act as generalized base catalysts in the enzymatic process.In this paper,the dissociation mechanism of monoprotonated arginine was studied by direct dynamics simulation.Among many direct kinetic simulation methods,thermal decomposition and collision induced dissociation were selected to study the single protonated arginine dissociation.For thermal decomposition,in the range of 1500-3000 K vibration simulation temperature,23 reaction channels are found to correspond to the mass charge ratio of 10 product ions.In this paper,the specific reaction process and reaction probability of 10 high reaction channels are presented in detail.According to the dissociation results combined with Rice-Ramsperger-Kassel-Marcus(RRKM)and the classical transition state theory,the reaction rate constants and kinetic parameters are obtained,which is valuable for identifying the large polypeptide molecules containing arginine and predicting the possibility of decomposition reaction.Based on the above results of thermal dissociation of monoprotonated arginine,collision-induced dissociation(CID)was also studied.A total of 108 reaction paths are obtained in the range of 10 e V-25 e V collision energy simulated in this paper.The reaction probability and specific reaction process diagram of 18 main reaction paths are shown here.The simulation results of thermal excitation and collision excitation arecompared to reveal the variation of the two dissociation mechanisms with excitation energy,which provides a reliable theoretical supplement and evidence for the experimental results.