Porphyrins

**Definition:** A group of compounds containing the porphin structure, four pyrrole rings connected by methine bridges in a cyclic configuration to which a variety of side chains are attached. The nature of the side chain is indicated by a prefix, as uroporphyrin, hematoporphyrin, etc. The porphyrins, in combination with iron, form the heme component in biologically significant compounds such as hemoglobin and myoglobin.

**Tree numbers:** - D03.383.129.578.840.500 - D03.633.400.909.500 - D04.345.783.500 - D23.767.727

**Synonyms:** - Porphyrin