CH 8 Iron Kinetics

What are the 2 DIETARY forms of Iron that can be absorbed?

1. Heme

2. Nonheme

Which form of iron is associated with ANIMAL FOOD?

Heme Iron

Which type of iron is associated with PLANT FOOD?

NONheme iron

In HEME IRON kinetics, which enzyme releases iron from heme

Heme Oxygenase HO-1

Which type of iron enters the enterocyte DIRECTLY?

Heme iron

Enters and is essentially extracted by HO-1

In NONHEME Iron kinetics, which protein converts Fe3+ to Fe2+ BEFORE absorption?

Duodenal cytochrome b (Dcytb)

In NONHEME kinetics, which transporter carries the Fe2+ into the intestinal cell (enterocyte)

DMT 1

Divalent Metal Transporter

What is the STORAGE FORM of Iron?

FERRITIN

In IRON KINETICS which protein EXPORTS iron from the intestinal cell into the blood?

Ferroportin

Which hormone REGULATES iron absorption into the BLOOD

Hepcidin

Which organ is responsible for the enzyme HEPCIDIN?

LIVER

HEPcidin

What happens to Ferroportin when hepcidin levels rise?

Hepcidin HIGH = Ferroportin activity LOW

Hepcidin will BLOCK FERROPORTIN

AS IRON LEAVES the enterocyte, which protein converts Fe2+ to Fe3+?

Hephaestin

Ones Iron enters circulation, which protein TRANSPORTS iron?

Transferrin

What is APOtransferrin?

This is transferrin WITHOUT any ferric iron bound to it

Why does Iron leaving the enterocyte get converted from the Ferrous (Fe2+) to the Ferric (Fe3+) state?

It is the FERRIC STATE (Fe3+) of Iron that binds to the APOtransferrin

How many FERRIC IRON molecules can Apotransferrin bind?

2 Fe3+ (ferric) Iron molecules

thus converting to transferrin

Once Iron is bound to Transferrin, where is the iron taken?

To different target cells