Apparent Induced Enzyme Formation due to Co-enzyme Deficiency


PREVIOUS studies by Happold and Hoyle1 and Dolby, Hall and Happold2 made it appear certain that the enzyme tryptophanase was induced in cultures of Escherichia coli only in response to the presence of tryptophan in the medium in which the cell was grown. It was not developed in a complete amino-acid medium which also contained glucose but, as was shown by Evans, Handley and Happold3, the tryptophan content of the medium remained unchanged, so that it was presumed that the fermentation of the carbohydrate gave conditions of culture comparable to the total absence of tryptophan in the medium. These studies were made either with enzyme preparations or with washed cells incubated with the substrate in the presence of toluene, which procedure reduced tryptophanase activity only slightly but did render the cells non-viable.

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  1. 1

    Happold, F. C., and Hoyle, L., Biochem. J., 29 1918 (1935); Brit. J. Exp. Path., 17, 136 (1936).

  2. 2

    Dolby, D. E., Hall, D. A., and Happold, F. C., Brit. J. Exp. Path., 33, 304 (1952).

  3. 3

    Evans, W. C., Handley, W. R. C., and Happold, F. C., Biochem. J., 35, 207 (1941).

  4. 4

    Happold, F. C., and Struyvenberg, A., Biochem. J. (in the press).

  5. 5

    Lichstein, H. C., Gunsalus, I. C., and Umbreit, W. W., J. Biol. Chem., 161, 311 (1945).

  6. 6

    Gale, E. F., “Advances in Enzymology”, 6, 1 (1946).

  7. 7

    Holden, J. T., Feirman, C., and Snell, E. E., J. Biol. Chem., 178, 789 (1949).

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HAKIM, A., HAPPOLD, F. Apparent Induced Enzyme Formation due to Co-enzyme Deficiency. Nature 174, 358–359 (1954) doi:10.1038/174358a0

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