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Why does total iron binding capacity increase in anaemia?

  1. Jun 22, 2010 #1
    Hello everyone,

    In anameia related to iron, plasma tranferring increases and iron decreases. How does this increase the total iron binding capacity of the enzyme. If I draw a sample of blood, there would be some transferrin enzymes in excess lowering iron binding capacity right? Thanks :smile:
     
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  3. Jun 22, 2010 #2

    Ygggdrasil

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    Transferrin is a protein that binds iron. The more transferrin in the blood, the more iron blood can bind. Therefore, when doctor test for total iron binding capacity, they are in effect, measuring the amount of transferrin present in the blood.
     
  4. Jun 22, 2010 #3
    Thanks for the reply :smile: Now lets say there are 2 moles of Fe and lots of enzymes. Then 2 moles of iron would bind to the enzyme, and the other enzymes would be free of iron, so wouldn't that lower the iron binding capacity. I'm thinking iron binding capacity as the amount of iron bound protein/number of protein multiplied by 100. Thanks :smile:
     
  5. Jun 22, 2010 #4

    Ygggdrasil

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    Yes, the fractional occupancy of transferrin (percent of iron binding sites occupied by iron) would be lower if you either increase the amount of transferrin or decrease the amount of iron. However, the transferrin still retains the capacity to bind additional iron.

    Total iron binding capacity is defined as the amount of iron that can be bound by the transferrin in a certain volume of blood. The definition does not involve the fractional occupancy of the transferrin.
     
  6. Jun 22, 2010 #5
    Right so eg if there 10 moles of Fe, and normally only 3 binded, when there are more enzymes around 7 bind so that means capacity has increased. Thanks Yggdrasil for correcting the misunderstanding :smile:
     
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