User:Ulfrannug/sandbox/6-formylindolo(3,2-b)carbazole

6-formyl-indolo(3,2-b)carbazole 6-formyl-indolo(3,2-b)carbazole (FICZ) is a nitrogen heterocycle with an extremely high affinity (Kd = 7 x 10−11 M) for binding to the Aryl hydrocarbon receptor (AhR) }länk till Receptor sidan i Wikipedia. It was originally identified as a photooxidized derivative of the amino acid tryptophan and suggested to be the endogenous ligand of the AhR.