Which iron oxidation states are toxic to humans?

[Rajini]

Hello all,

Which iron is toxic (Fe 1+, Fe2+, Fe3+, etc ?).
Or is it poisonous whenever one takes excess of any form or iron ?
Somewhere i read that free iron is toxic. Is that means iron with zero oxidation state?
In wiki (for 'iron'), i read that 'Large amount of ingested iron is problematic' What does ingestion means?

thanks

 

[madcat8000]

Iron is usually only toxic because it catalyzes the breakdown of the oxide H2O2 into the super dangerous hydoxyl radicals HO. It is normaly only biologicaly active in the Fe+3 form and won't normaly be absorbed if not in that form.(Technicly +3 originaly, then +2 to get into the gut lineing then back to +3 for transprotation) Unless it was a specialy desgined supplment I can't imagine any way to eat too much iron.

Normaly iron is almost never found free in the body but is locked up tightly in molecules that block all contact as storage(transferrin) or in enzymes that usually only allow a few reactions to take place. However an over abundance will allow too many chances for escape and it can cause damage where ever it is.

The body doesn't readily take up iron and the most common way to get "iron overload" is from having had too many blood transfusions either because of various surgeries or because the transfusions were to treat Haemophilia or Sickle cell anemia. Haemochromatosis is the name of a genitic(primary) or acquired(secondary) disease that also causes iron overload metabolicly. As the body doesn't have a natural way of excreting excess iron the current treatment is blood letting. Simular to blood donation except that it is dosposed of.

http://en.wikipedia.org/wiki/Human_iron_metabolism

http://en.wikipedia.org/wiki/Hemochromatosis#Terminology

 

[Rajini]

Normaly iron is almost never found free in the body but is locked up tightly in molecules that block all contact as storage(transferrin) or in enzymes that usually only allow a few reactions to take place. However an over abundance will allow too many chances for escape and it can cause damage where ever it is.

Thanks. Iron is almost never found free...this means it can be any, e.g., Fe or Fe(II) or Fe(III), etc [i understand from your reply that Fe(III) and Fe(II) are biologically usefull].
Is there some source for your words..because i need to give reference in my report!

 

[madcat8000]

Can you cite a web site? Most of my knowledge is gathered over the last ten years and I wasnt collecting sources lol! This site seems to have a lot of good general information on the subject:

http://themedicalbiochemistrypage.org/heme-porphyrin.html

And I don't think you can say that iron is only in the +2 or +3 oxidation states, would be better to hedge bets and say something like "almost always" because there might be a few exmples of other states.

 

[Rajini]

Hi,

I got your point! And that link is quite helpful.
thanks.

 

[bobze]

Can you cite a web site? Most of my knowledge is gathered over the last ten years and I wasnt collecting sources lol! This site seems to have a lot of good general information on the subject:

http://themedicalbiochemistrypage.org/heme-porphyrin.html

And I don't think you can say that iron is only in the +2 or +3 oxidation states, would be better to hedge bets and say something like "almost always" because there might be a few exmples of other states.

The vast majority of iron in our bodies is ferrous (Fe II), which is found in the plentiful heme's of hemoglobin and myoglobin. Our bodies actually go to great lengths to reduce ferric (Fe III) iron, especially in the blood and heme groups, with the help of such creatively named enzymes as "ferrimyglobin reductase" lol (those biochemists are so creative!)