FIG.7. Metabolic scheme illustrating the biotransformation of TCP to mutagenic metabolites. Oxidation of TCP at carbon 2 leads to an unstable gem-chlorohydrin which spontaneously loses HCI to form DCA. DCA can then be reduced, by the addition of ADH, to the alcohol, 1,3-dichloro-2-propanol (1,3-DCP). In the presence of N-acetylcysteine (RSH), DCA is conjugated to form PDM. Oxidation of TCP at carbon 1 also leads to an unstable gem-chlorohydrin which spontaneously loses HCI to form 2,3-dichloropropanal, which in the presence of ADH is reduced to 2,3-dichloropropanol (2,3-DCP).