Indole is a metabolic byproduct of tryptophan metabolism produced by hydrolysis and deamination. Its presence indicates the presence of tryptophanase.
Culture require: media rich in tryptophan
Reagent: p-dimethylaminobenzaldehyde, which is present in Kovac's and Ehrlich's reagent
Indole reacts with p-dimethylaminobenzaldehyde to produce a red-violet compound (di[4-(indole-3-yl-methylene)-2,5-cyclohexadien-1-ylidene]-dimethyl-ammonium)
