Iron Flashcards
What is the difference between Fe2+ and Fe3+?
Fe2+: also known as ferrous is heme iron which means it has hemoglobin and myoglobin and is found only in meat products
Fe3+: also known as ferric iron is non-heme iron and is found in plant sources
Which form of iron is best for absorption?
Fe2+
Which form of iron is best for transport?
Fe3+
Which vitamin enhances iron absorption
Vitamin C
Explain in detail how iron is absorbed
In the small intestine
- For non-heme iron: Ferrireductase in the brush boarder converts Fe2+ to Fe3+
- This is then transported across the membrane by DMT1 transporter protein
- For heme iron: transported across the membrane by HCP1
- Heme oxygenase converts heme-iron to Fe2+
- Ferritin acts as a mucosal block to prevent too much absorption
- From here Ferroportin transports Fe2+ across the membrane into the bloodstream
- Ferroxidase then converts Fe2+ to Fe3+ for transport through the body
- Fe3+ then attaches to Transferrin
What is DMT1?
A protein transporter on the brush boarder of the enterocyte which is responsible for transporting non-heme iron
What is HCP1?
A protein transporter on the brush boarder of the enterocyte which is responsible for transporting heme iron across the membrane
What is the role of heme oxygenase?
Converts heme-iron (Fe3+) to Fe2+
What is the role of Ferritin?
It acts as a mucosal block within the enterocyte to prevent too much absorption of iron
What is the role of Ferroportin?
A transporter protein in the basolateral membrane whichis responsible for transporting Fe2+ our of the enterocyte and into the blood stream
What is the role of Ferroxidase?
Ferroxidase is a protein situated in the basolateral membrane of eneterocytes and converts Fe2+ to Fe3+ for transport as it leaves the cell
Where is iron stored in the body?
Liver, bone marrow, spleen,
How is iron excreted?
only 10 is excreted through faeces
90% is recycled
What are the functions of iron?
Needed for haemoglobin to transport oxygen
- 4x Fe containing heme rings bind 1 oxygen each
Needed for myoglobin (takes oxygen from red blood cells to muscle and heart cells)
- 1x Fe containing heme ring binds 1 oxygen
Oxidation – reduction reactions. Can be harmful in too high amount, as iron forms free radical compounds
Immune system: required for lymphocytes
and natural killer cells production
Iron containing metalloenzymes
What is caused by an iron deficiency?
- few symptoms initially
- develops to iron-deficiency anaemia (= microcytic hypochromic anaemia)
- decreased hemoglobin and serum ferritin levels, transferrin receptors number increases
- Symptoms include: fatigue, shortness of breath, depression, poor immunity, spoon shaped nails
