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haem Line breaks: haem
(US heme)

Definition of haem in English:


[mass noun] Biochemistry
An iron-containing compound of the porphyrin class which forms the non-protein part of haemoglobin and some other biological molecules.
Example sentences
  • This turnover releases significant amounts of the iron-free portion of heme, porphyrin, which is subsequently degraded.
  • The majority of photosensitizers are derivatives of hematoporphyrin, a synthetic porphyrin synthesized from heme.
  • The active site or prosthetic group of all the cytochromes is an iron containing porphyrin, or heme.


1920s: back-formation from haemoglobin.

Definition of haem in:
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