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heme
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class=skin-invert-image|thumb|420 px|Binding of oxygen to a heme prosthetic group Heme (American English), or haem (Commonwealth English, both pronounced /hi:m/ ), is a ring-shaped iron-containing molecule that serves as a ligand of various proteins, especially as a component of hemoglobin, which carries oxygen in the bloodstream. It is composed of four pyrrole rings with two vinyl and two propionic acid side chains. Heme is biosynthesized in both the bone marrow and the liver.
~17 min read
Article
12 sectionsContents
- Function
- Types
- Major hemes
- Other hemes
- Use of capital letters to designate the type of heme
- Synthesis
- Synthesis for food
- Degradation
- In health and disease
- Cancer
- Genes
- Notes and references
class=skin-invert-image|thumb|420 px|Binding of oxygen to a heme prosthetic group Heme (American English), or haem (Commonwealth English, both pronounced /hi:m/ ), is a ring-shaped iron-containing molecule that serves as a ligand of various proteins, especially as a component of hemoglobin, which carries oxygen in the bloodstream. It is composed of four pyrrole rings with two vinyl and two propionic acid side chains. Heme is biosynthesized in both the bone marrow and the liver.
Heme plays a critical role in several redox reactions in mammals, due to its ability to carry the oxygen molecule. Reactions include oxidative metabolism (cytochrome c oxidase, succinate dehydrogenase), xenobiotic detoxification via cytochrome P450 pathways (including metabolism of some drugs), gas sensing (guanyl cyclases, nitric oxide synthase), and microRNA processing (DGCR8).