Prodigiosin is a red dye produced by many strains of the bacterium Serratia marcescens,[1][2] as well as other Gram-negative, gamma proteobacteria such as Vibrio psychroerythrus and Hahella chejuensis.

It is responsible for the pink tint occasionally found in grime that accumulates on porcelain surfaces such as bathtubs, sinks, and toilet bowls.

[11] As a result, prodigiosin is a highly promising drug lead, and is currently in preclinical phase study for pancreatic cancer treatment.

[12] Prodigiosin has recently been found to have excellent activity against stationary phase Borrelia burgdorferi, the causative agent of Lyme disease.

[13] The biosynthesis of prodigiosin[15][16] and related analogs, the prodiginines[3][14] involves the convergent coupling of three pyrrole type rings (labeled A, B, and C in figure 1) from L-proline, L-serine, L-methionine, pyruvate, and 2-octenal.

This fragment is then able to react with the masked carbanion formed from the pyridoxal phosphate (PLP) mediated decarboxylation of L-serine, which cyclizes in a dehydration reaction to yield the second pyrrole ring.

Finally, the two pieces are combined by pigC and its cofactor adenosine triphosphate (ATP) in a dehydration reaction which establishes a conjugated system across all three rings and completes the synthesis of prodigiosin.