The Origin of the Methyl Group in Mesaconate Formed From Glutamate by Extracts of Clostridium Tetanomorphum

SUMMARY Cell-free extracts of Clostridium tetanomorphum convert glutamate-4-Cl4 to mesaconate-Cl4 which is labeled exclusively in the carbon atom adjacent to the methyl group. This and other tracer evidence prove, first, that the methyl carbon atom of mesaconate is derived from carbon atom 3 of gluta- mate and, second, that the formation of the branched chain structure of mesaconate results from cleavage of the bond between carbon atoms 2 and 3 of glutamate, or a straight chain compound derived thereof, and forma- tion of a new bond between carbon atoms 2 and 4. BIBLIOGRAPHY 1. Wachsman, J. T., J. Biol. Chem., 223, 19 (1956). 2. Flavin, M., Ortia, P. J., and Ochoa, S., Nature, 176, 823 (1955). 3. McIlwain, H., J. Gen. Microbial., 2, 288 (1948). 4. Tabor, H., and Hayaishi, O., J. Biol. Chem., 194, 171 (1952). 5. Mosbach, E. H., Phares, E. F., and Carson, S. F., Arch. Biochem. and Biophys., 33, 179 (1951). 6. Tabor, H., in McElroy, W. D., and Glass, B., Amino acid metabolism, Balti- more, 373 (1955). 7. Jones, A. R., Dowling, E. J., and Skraba, W. J., Anal. Chem., 25, 394 (1953). 8. Ginger, L. G., J. BioZ. Chem., 166, 453 (1944). 9. Katz, J., Abraham, S., and Chaikoff, I. L., Anal. Chem., 27, 155 (1955). 10. Wachsman, J. T., and Barker, H. A., J. BioZ. Chem., 217, 695 (1955). 11. Barker, H. A., Wilson, R. M., and Munch-Petersen, A., Federation Proc., 16, 151 (1967).