Definition of haem in English:

haem

(US heme)

noun

Biochemistry
  • [mass noun] An iron-containing compound of the porphyrin class which forms the non-protein part of haemoglobin and some other biological molecules.

    • ‘This turnover releases significant amounts of the iron-free portion of heme, porphyrin, which is subsequently degraded.’
    • ‘The active site or prosthetic group of all the cytochromes is an iron containing porphyrin, or heme.’
    • ‘The majority of photosensitizers are derivatives of hematoporphyrin, a synthetic porphyrin synthesized from heme.’
    • ‘An iron porphyrin, called heme, is the portion of hemoglobin that carries oxygen from the lungs to our body's cells.’
    • ‘The harvested cell pellet was red, which suggested that the prosthetic group heme was synthesized by the bacterium.’

Origin

1920s: back-formation from haemoglobin.

Pronunciation:

haem

/hiːm/