TRYPTOPHAN REACTION WITH FREE-RADICALS ARISEN FROM CARBON-TETRACHLORIDE IN A MODEL SYSTEM - A MASS-SPECTROMETRIC STUDY

The interaction between free radicals derived from the thermal decompo sition of carbon tetrachloride and N-acetyl-d,l-tryptophan ethyl ester (TRPAE) under anaerobic and aerobic conditions was studied, The struc ture of the reaction products formed was deciphered by the GC/MS analy sis of their trimethylsilyl derivatives, Under anaerobic conditions no formation of reaction products was detected, Under aerobic conditions the following products were identified: 1. A chloro hydroxy unsaturat ed adduct of TRPAE (2 isomers). 2. A dichloro hydroxy unsaturated addu ct of TRPAE . 3. 12 products which are different pyrrolo[2,3-b]indol d erivatives. Some of the products appeared to have an hydroxyl group as a substituent, all of them contained chlorine and only one contained carbon from CCl4. Interestingly, the formation of those adducts not co ntaining CCl3 would be missed during the regular procedures toxicologi sts use to determine the so-called 'covalent binding' employing (CCl4) -C-14. Concerning the potential relevance of these findings, we hypoth esize that if interactions similar to those here reported occurred at least in part during CCl4 poisoning, the resulting critical proteins c ontaining tryptophan, e,g, membrane or other and enzymes containing th e amino acid in their active center, might be impaired.