The porphyrins and their closely related molecules are essential to all plants and animals. An iron porphyrin, called heme, is the portion of hemoglobin that carries oxygen from the lungs to our body's cells. The heme of another protein, myoglobin,...

A porphyrin is a heterocyclic macrocycle derived from four pyrroline subunits interconnected via their α carbon atoms via methine bridges (=CH-). The macrocycle, therefore, is a highly-conjugated system, and, as a consequence, is deeply coloured - the...