On the Physiological Properties of Mimosine

1. Mimosine inhibits the growth of E. coli, and the inhibition is antagonized by tryptophane, proline, histidine, tyrosine, phenylalanine, alanine, serine and IAA.2. The growth inhibition by mimosine disappeared on incubating for a few days. This loss of the antibacterial action is probably due to the destruction of mimosine by an enzyme (probably adaptively) formed by E. coli. Alanine and serine were detected chromatographically in the cultures which contained mimosine.3. An enzyme preparation is obtained from the pulvini of M. pudica, which splits mimosine. A spot corresponding to serine is paper-chromatographically detected from the reaction mixture. The optimal pH is about 8.4. In view of the result obtained, the mechanism of sleeping movement in the mimosa plant was discussed.