Tryptophan is an α-amino acid that is used in the biosynthesis of proteins. Tryptophan contains an α-amino group, an α-carboxylic acid group, and a side chain indole, making it a polar molecule with a non-polar aromatic beta carbon substituent. The molecular formula is C11H12N2O2 and the monoisotopic mass is 204.0899 Da; the common molecular weight is 204.23 g mol−1. The indole chromophore gives strong UV absorbance near 280 nm, making tryptophan useful for spectroscopic protein analysis. Tryptophan is chiral and the L enantiomer is the biologically incorporated form. Relevant physicochemical data include pKa values of the carboxyl and amino groups near 2.4 and 9.4 respectively, and an isoelectric point around 5.9. It is synthesized biologically through the shikimate pathway via anthranilate intermediates in plants and microorganisms. In aqueous systems tryptophan is amphoteric, sparingly soluble in water at neutral pH relative to small polar amino acids, and can undergo common reactions of amino acids including peptide bond formation, decarboxylation to tryptamine, and oxidative pathways to kynurenine under enzymatic control.
Parent: Tryptophan
Parent: Tryptophan
Parent: Tryptophan
Parent: Tryptophan
Parent: Tryptophan
Parent: Tryptophan
Parent: Tryptophan
Parent: Tryptophan
Parent: Tryptophan
Parent: Tryptophan
Typical high purity L tryptophan specifications used in pharmaceutical and food ingredient supply chains call for an assay of at least 98.0 percent on a dry basis with total related compounds generally controlled to 1.0 percent w w or below and any single related compound limited to 0.3 percent w w or less. Known related compounds and impurities monitored by HPLC and mass spectrometry include 5 hydroxytryptophan, N acetyltryptophan, indole 3 acetic acid, oxindolylalanine, kynurenine, tryptamine and dimeric or ethylidene linked tryptophan species. Residual solvents are controlled to ICH Q3C limits, and elemental impurities and heavy metals are maintained within applicable pharmacopeial limits rather than exceeding regulatory thresholds. Typical moisture content is kept low to stabilize the material and oxidative or racemization products are minimized by appropriate storage and GMP production controls.
Tryptophan serves as an essential amino acid incorporated into proteins and as a biochemical precursor for several important metabolites, notably serotonin and melatonin via the serotonin synthetic pathway, and kynurenine pathway metabolites that participate in immune and redox biology.
Foods highest in tryptophan are protein rich sources such as poultry including turkey and chicken, eggs, dairy products like cheese, fish, beef, soy products and seeds and nuts; turkey is commonly cited but many animal and certain plant proteins contain substantial levels.
Tryptophan is not classified as a conventional antidepressant drug; it is a serotonin precursor and can influence central serotonin synthesis when administered in sufficient amounts or combined with other interventions, but clinical antidepressant effects are variable and prescription antidepressants remain the standard treatment for depressive disorders.
In 1989 a contaminant profile associated with a particular industrial production batch of L tryptophan was linked epidemiologically to cases of eosinophilia myalgia syndrome, prompting a temporary regulatory ban in some jurisdictions; the causal factors were traced to specific manufacturing changes that produced unusual impurities, and modern manufacturing controls and regulatory oversight have since addressed those risks.
