The central goal of the proposed project is the determination of possible chemical processes that might explain the protective properties of certain fatty acids in certain tumor and cancer initiation in vivo experiments. The specific aims of this study are: 1) Determine the necessary chromatographic conditions required to separate the products of the studied reaction; 2) Isolate the components and unequivocally identify the structure of the reaction products; 3) Establish, by adequate control experiments, which products arise from the interaction of the detoxifying agent and the fatty acid radical and those of fortuities reactions independent of the agent; and, 4) Construct a detoxifying scheme that explains the experimental results. The experimental methods will employ a combination of enzymology, organic synthesis, analytical liquid chromatography, spectrometry and spectrophotometry. In summary, the experimental methodology will be executed in four phases: 1) Starting materials will be prepared by methods described in the literature and proven in the hands of the principal investigator, that is, the (S)-13-hydroperoxy isomer derived from linoleic acid and a synthetic CLA ester; 2) The hydroperoxide is decomposed by an iron (III) porphyrin in dichloromethane in the presence and absence of the CLA ester; 3) The components of the reaction mixture are separated by chromatographic techniques and isolated for characterization; and, 4) The products are identified by spectral methods and the experimental results are correlated in the detoxification scheme. The long-term goals of the research project lie in understanding the chemistry of the interacyion of dietary PUFA and CLA and the apparent protective ability of the latter against certain tumors. Given the importance in understanding the role of dietary PUFA in tumorigenesis and carcinogenesis and the inhibition of these processes, the proposed study explores plausible in vitro termination reactions of lipid hydroperoxide metabolites mediated by CLA.