What is the Difference Between Heme and Hemin?

Heme and hemin are both iron-containing porphyrin molecules, but they have different structures and properties:

1. Iron ion: Heme contains a ferrous ion (Fe2+), while hemin contains a ferric ion (Fe3+).
2. Coordinating ion: The coordinating ion in heme is a hydroxide ion, whereas in hemin, it is a chloride ion.
3. Chemical structure: Heme does not contain chloride atoms, whereas hemin molecules contain chloride atoms in their structure.
4. Source: Hemin can be formed from heme, such as heme B found in human blood, and is endogenously produced in the human body during the turnover of old red blood cells. Heme, on the other hand, is a biochemical substance necessary for binding oxygen in the bloodstream.

In summary, the key difference between heme and hemin lies in the iron ion, coordinating ion, and the presence of chloride atoms in their respective chemical structures.

Comparative Table: Heme vs Hemin

Heme and hemin are both porphyrin protein molecules, but they have some differences in their structure and composition. Here is a table summarizing the differences between heme and hemin:

Heme is a biochemical substance necessary for binding oxygen in the bloodstream, while hemin is a component of heme B used in various biological functions. Both heme and hemin are coordination complexes, containing iron ions.