| Abstract: | Thaumatin, an intensely sweet-tasting protein, completely blocksthe motility of Escherichia coli at concentrations  0.01%. Thismotility is restored if the phosphate concentration in the suspensionis increased to 0.025 mol/l. Unlike native thaumatin, chemicallymodified thaumatin with one acetyl group attached to the  -aminogroup of the lysine residue is a good attractant for E. colilike, e.g., L-serine. Hypotheses have been constructed to explainthe action observed for thaumatins and phosphate. It is suggestedthere might be a similarity between the chemotactic activitiesof bacteria and the sensory responses in humans. |
