Heme and Iron Metabolism

Question 1

Role of Cytochrome B and where is it found?

Answer 1

Cyt B reduces Fe3+ to Fe2+ in the duodenum

Question 2

Role of Ferritin

Answer 2

Fe2+ storage

Question 3

Role of Ferroportin

Answer 3

Fe2+ exporter

Question 4

Role of Hepaestin

Answer 4

Oxidizes Fe2+ to Fe3+ so that it can be carried by transferrin

Question 5

Role of Transferrin

Answer 5

Fe3+ binding protein for delivery of iron throughout the body

Question 6

Role of Tf-R1 and Tf-R2

Answer 6

Tf-R1 and Tf-R2 bind transferrin with loaded Fe3+

nb: Tf-R1 is inacitvated by HFE, Tf-R2 is not effected by HFE

Question 7

Role of Enterocyte in Iron absorption

Answer 7

Absorbs Fe2+ via DMT after it has been reduced by Cyt B
Stores Fe2+ as Ferritin
Fe2+ can be exported via ferroportin

Question 8

Role of Hepcidin

Answer 8

Produced by hepatocytes
Master Hormone regulating iron export
Binds to ferroportin and degrades export

Question 9

Factors controlling hepcidin

Answer 9

Iron Content
Anemia/Hypoxia
Inflamation/Infection

Question 10

Hierarchy of controlling factors

Answer 10

Inflammation/Infection > Anemia/Hypoxia > Iron Content