Multifaceted roles of arginine in cellular function, signaling, and disease.

Arginine, also known as L-arginine residue, is a dibasic, cationic, conditionally essential amino acid that serves as an integral part of polypeptide chains. Along with its conventional role in protein synthesis, numerous biological processes depend on L-arginine, such as the synthesis of nitric oxide (NO) and regulation of vascular tone, the urea cycle and acid/base homeostasis, nuclear localization, post-transcriptional and post-translational modifications, signal transduction, the transport system, and viral genome assembly. In the physiological context, it plays diverse roles; for example, it correlates with airflow abnormalities in severe asthma, reduces inflammation, promotes muscle regeneration, and improves blood flow through vasodilation. Keeping in view the above, this review is an effort to collate the current knowledge and discuss and appraise the biological and physiological roles of L-arginine as an integral entity within a biological system.