In August 1990, CDC and the Food and Drug Administration proposed a structure for peak 97, the high performance liquid chromatographic (HPLC) peak that was most predictive of L-tryptophan (LT) lots associated with eosinophilia-myalgia syndrome (EMS) cases.1 This report updates those findings.
Analyses of the product of LT and acetaldehyde show that the product is di-L-tryptophan animal of acetaldehyde (DTAA), with the methine bridge coupling two tryptophan molecules across the indole nitrogens rather than amino nitrogens. This synthesized product has the same proton nuclear magnetic resonance (NMR) spectra, mass spectra, and HPLC chromatographic properties as peak 97. Key information to support the location of the methine bridge was provided by the analyses of synthesized product using a two-dimension longrange 13C-1H shift correlation NMR spectroscopic experiment,2 which demonstrated that the methine proton of the acetaldehyde residue is coupled to carbon 2 and 2' of the LT groups and
Update: Analysis of L-Tryptophan for the Etiology of Eosinophilia-Myalgia Syndrome. Arch Dermatol. 1991;127(1):18. doi:10.1001/archderm.1991.01680010022003