Molecular and Cellular Radiobiology Project Title: Mechanisms of Action of Free Radicals and Hormones RX-03-02-(c) 1?. Expected Results in FY 1974: (Cont'd,) studies, and during the past two years Bielski has begun to apply radiolysis procedures to the study of biochemical redox reactions, including enzymic ones; while Holroyd is also employing pulse radiolysis to study the same materials, An on-line EPR/radiation facility would add significant scope to this work. For several years P. Levy of the Solid State Physics group has been interested in setting up .n on-line EPR/radiation station at BNL's Dynamitron accelerator for the study of irradiated solids. reduction in operating funds for the group, Prior to the equipment for the EPR components was acquired including special magnets axially bored to permit unperturbed transport of the electron beam; and a beam pipe and "cave" compatible with EPR use have been provided. Several years ago Levy and Mattern expressed strong interest in collaboration with us on radiobiological and radiochemical studies using the proposed EPR facility at the Dynamitron, provided that we be responsible for the special microwave cavities and other equipment required for aqueous solution work, In the interim, however, the Physics Department budget has forced termination of the development work, Mattern has left BNL, and the incomplete EPR facility is in limbo. During the past year informal exploratory meetings were held between members of BNL Chemistry and Medical Departments regarding possible collabora-= tion in applying radiochemical and pulse radiolysis techniques to biomedical research in conjuction with EPR capability, especially flow systems for studying transient free radical intermediates, An on-line EPR/radiation facility would be of the greatest importance in supporting this proposed collaboration. . The facility would utilize present equipment and experimental rooms of the Physics Department and would require a full-time junior scientist plus an estimated $10,000 for initial installation. Although justified here in terms of radiation biophysics, non-radiation biochemistry, and the correlation of free radical mechanisms between the two, the facility would also be a uniquely powerful analytical tool in research on free radicals of pollutants, as is pointed out in the supplementary 189, (Borg) A number of peptides of histidine and cysteine will be prepared by the dinitrophenylene bridging method, both to demonstrate the method and for the acquig$tion of several hormone analogs not otherwise obtainable. The dinit henylene bridging method will be extended to peptides of tyrosine if poss ie. Itc is planned to put into use the first system of enzymatic deprotection and to combine the attachment and deprotection work into a system of solid phase peptide synthesis which allows for preparation of hormone analogs entirely in aqueous solution at abouc physiological conditions of pH and temperature. (Schwartz, Walter) (See Continuation Sheet) 1119306 RX- 246