Arginine can significantly affect the efficiency of backbone fragmentation of protonated peptides. In the present work, the thermal decomposition mechanisms of singly protonated arginine are investigated by using direct dynamics simulations with PM6-D3 semi-empirical electronic structure theory. For vibrational temperatures of 1500–3000 K, totally 23 reaction channels have been determined, which correspond to 10 m/z values for product ions. The principal fragmentation patterns and mechanisms have been demonstrated and discussed in detail and compared with the experimental observations. The composition of the intense and uncertain m/z peaks in experiment has been assigned in the light of our simulation results. Competition with the backbone fragmentation, the highly basic guanidine group on the side chain, which readily fragments, plays an important role in the dissociation patterns.

精氨酸可显着影响质子化肽的骨架断裂效率。在目前的工作中，通过使用PM6-D3半经验电子结构理论的直接动力学模拟，研究了单质子化精氨酸的热分解机理。对于1500-3000 K的振动温度，总共确定了23个反应通道，对应于产物离子的10  m / z值。主要的碎裂模式和机制已得到证实和详细讨论，并与实验观察结果进行了比较。激烈而不确定的m / z的组成已根据我们的模拟结果指定了实验中的峰。与主链断裂的竞争，即易于断裂的侧链上的高碱性胍基在解离模式中起重要作用。