Definition of porphyrin in US English:



  • Any of a class of pigments (including heme and chlorophyll) whose molecules contain a flat ring of four linked heterocyclic groups, sometimes with a central metal atom.

    • ‘These observations suggest that the generation of 102 by lipophilic porphyrins occurs within the bilayer, which is also the site of damage.’
    • ‘In this work a systematic study of the photophysical properties of four cationic porphyrins in liposomes is performed and results are compared with those found in homogeneous media.’
    • ‘The NSD method has been used extensively to describe and analyze the out-of-plane distortions of porphyrins in heme proteins.’
    • ‘Changes in apoprotein and porphyrin fluorescence suggest two classes of bound porphyrins.’
    • ‘It should also be noted that the doming deformation in the NSD context does not involve the iron, but only the 24 atoms of the porphyrin ring.’
    • ‘The researchers used a nanoparticulate semiconductor electrode coated with a light-sensitive porphyrin or chlorophyll dye.’


Early 20th century: from Greek porphura ‘purple’ + -in.