L-arginine (Arg)

L-arginine is a semi-essential amino acid that serves as a critical building block for proteins and a precursor for the signaling molecule nitric oxide (NO), polyamines, and creatine (PMID: 30305513). In the extracellular environment, its concentration is tightly regulated and plays a pivotal role in modulating immune cell function, particularly T-cell proliferation and activation (PMID: 27239040). Many tumors exhibit arginine auxotrophy due to the silencing of argininosuccinate synthetase 1 (ASS1), making them dependent on the uptake of extracellular L-arginine for survival. Therapeutic strategies often involve the use of pegylated enzymes, such as arginine deiminase (Pegargiminase) or arginase (BCT-100), to deplete extracellular L-arginine, thereby selectively inducing metabolic stress and apoptosis in auxotrophic cancer cells (PMID: 29735914). Conversely, maintaining or increasing L-arginine levels is explored in cardiovascular health to support NO-mediated vasodilation and in immunotherapy to enhance T-cell anti-tumor activity. This dual role makes extracellular L-arginine a unique metabolic target in both oncology and metabolic medicine.

Other names

(S)-2-Amino-5-guanidinopentanoic acidArginineL-Arg

Enzymatic depletion of extracellular L-arginine to induce metabolic starvation in arginine-auxotrophic tumors or replacement therapy to lower toxic arginine levels in metabolic disorders (PMID: 30305513, PMID: 29735914).