What are porphyrins?

Building blocks: Porphyrins are building block molecules which form part of heme a major component of hemoglobin, the oxygen carrying molecule in blood. Porphyrins are also photoreactive which means when exposed to certain wavelengths of light they can induce cell killing reactions and have been used in superficial bladder cancer by giving them IV and shining a light into the bladder which can kill cancer cells.