Tags: Chemical Compound, Chemical Substance.
Hydroxymethylbilane (HMB) also known as preuroporphyrinogen is a molecule involved in the metabolism of porphyrin. In the third step it is generated by the enzyme porphobilinogen deaminase and in the next step the enzyme uroporphyrinogen III synthase converts it into uroporphyrinogen III. In general defects of heme synthesis after formation of HMB lead to photosensitivity.
