Arginine methylation is a prevalent post-translational modification in eukaryotic cells. Two significant debates exist within the field: do these enzymes dimethylate their substrates in a processive or distributive manner, and do these enzymes operate using a random or sequential method of bisubstrate binding? We reveal human protein arginine N-methyltransferase 1 (PRMT1) enzyme kinetics are dependent on substrate sequence. Further, peptides containing a Nη-hydroxyarginine generally demonstrate substrate inhibition and have improved KM values, which evokes a possible role in inhibitor design. We also reveal that the perceived degree of enzyme processivity is a function of both cofactor and enzyme concentration, suggesting that previous conclusions about protein arginine N-methyltransferase (PRMT) sequential methyl transfer mechanisms require reassessment. Finally, we demonstrate a sequential ordered Bi Bi kinetic mechanism for PRMT1 based on steady-state kinetic analysis. Together, our data point towards a PRMT1 mechanism of action and processivity that may also extend to other functionally and structurally conserved PRMTs.

中文翻译：

---

PRMT1的动力学分析揭示了多因素的持续性和顺序有序的机制

精氨酸甲基化是真核细胞中普遍的翻译后修饰。在该领域内存在两个重要的争论：这些酶是否以增效或分散的方式二甲基化其底物，这些酶是否使用随机或顺序的双底物结合方法起作用？我们揭示了人类蛋白质精氨酸N-甲基转移酶1（PRMT1）酶动力学取决于底物序列。此外，含有N n-羟基精氨酸的肽通常表现出底物抑制并且具有改善的KM值，这引起了抑制剂设计中的可能作用。我们还发现，感知到的酶的合成能力程度是辅因子和酶浓度的函数，提示有关蛋白质精氨酸N-甲基转移酶（PRMT）顺序甲基转移机制的先前结论需要重新评估。最后，我们基于稳态动力学分析证明了PRMT1的有序Bi Bi动力学机理。总之，我们的数据指向PRMT1的作用机制和过程，也可能扩展到其他在功能和结构上均受保护的PRMT。