In addition to its role in the Krebs cycle, α-ketoglutarate (2-oxoglutarate) has roles as a substrate or modulator of enzymes. 5-Octyl-α-ketoglutarate, also known as α-ketoglutarate octyl ester, is a stable, cell-permeable molecule that generates free α-ketoglutarate upon hydrolysis of the ester bond by cytoplasmic esterases. It is used in experiments to increase levels of intracellular α-ketoglutarate. 5-Octyl-α-ketoglutarate has been shown to modulate a variety of enzymes and signaling pathways, particularly in the context of glycolysis, hypoxia, and cancer.
Tryptophan is an amino acid precursor of serotonin and melatonin. DL-Tryptophan octyl ester is a tryptophan derivative with an octyl ester protected COOH group. This addition creates a stable, cell-permeable molecule capable of generating free tryptophan upon hydrolysis of the ester bond.