Heme vs. Haem — What's the Difference?

Heme, or haem (spelling differences) is a substance precursive to hemoglobin, which is necessary to bind oxygen in the bloodstream. Heme is biosynthesized in both the bone marrow and the liver.In microbiological terms, heme is coordination complex "consisting of an iron ion coordinated to a porphyrin acting as a tetradentate ligand, and to one or two axial ligands." The definition is loose, and many depictions omit the axial ligands.

Variant of heme.

A deep red, iron-containing compound, C34H32FeN4O4, that constitutes the nonprotein component of hemoglobin and certain other proteins.

Standard spelling of from2=Canada

(biochemistry) The component of hemoglobin (and other hemoproteins) responsible for binding oxygen. It consists of an iron ion that binds oxygen and a porphyrin ring that binds the globin molecules; one molecule binds one molecule of oxygen.

A complex red organic pigment containing iron and other atoms to which oxygen binds

A complex red organic pigment containing iron and other atoms to which oxygen binds