Definition from Wiktionary, the free dictionary
- Rhymes: -iːm
Alternative forms 
- heme (US)
- The component of haemoglobin responsible for binding oxygen, consists of an iron ion that binds oxygen and a porphyrin ring that binds the globin molecules; one molecule binds one molecule of oxygen.
- 2010, Pierre Cornelis and Simon Andrews (editors), Iron Uptake and Homeostasis in Microorganisms, page 17: