1-methyl-tryptophan

**1-methyl-tryptophan** is a synthetic tryptophan analog that exists as two stereoisomers (D- and L- forms). It is a competitive inhibitor of the enzyme **indoleamine 2,3-dioxygenase (IDO1)**, which is a rate-limiting enzyme in the kynurenine pathway responsible for tryptophan degradation[1][5]. The L-isomer acts as a weak IDO1 inhibitor and partial substrate, while the D-isomer (known as **Indoximod**) inhibits IDO2 and restores mTOR signaling under tryptophan starvation[1]. By inhibiting IDO1/IDO2, 1-methyl-tryptophan modulates immune responses, counteracting tryptophan-mediated immunosuppression (e.g., in cancer, chronic inflammation)[5]. It has low toxicity, good intestinal absorption, and low plasma protein binding[5][7]. Indoximod has undergone clinical trials for advanced melanoma and as an immunomodulatory agent in oncology[1][7].

Brand names

Indoximod

Other names

1-Methyltryptophan1-methyl-L-tryptophanL-Tryptophan, 1-methyl-L-(-)-1-Methyltryptophan(2S)-2-amino-3-(1-methylindol-3-yl)propanoic acidD-1-methyl-tryptophanD1-methyl-tryptophanD 1-methyl-tryptophan1-methyl-D-tryptophanABRINEPrecasinABRINE, L-H-METRP-OHH-Trp(1-Me)-OHN-ME-TRYPTOPHAN1-methyltryptophane