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12.73: Iron Functions

As we talked about in the previous subsection, there are 3 primary functional iron subcompartments.

1. Hemoglobin

2. Myoglobin

3. Iron-containing enzymes

Hemoglobin contains heme that is responsible for red blood cells’ red color. Hemoglobin carries oxygen to tissues. The function of hemoglobin can be seen in the link below.

Web Link

Hemoglobin

Myoglobin is similar to hemoglobin in that it can bind oxygen. However, instead of being found in blood, it is found in muscle. The color of meat products is a result of the state that myoglobin is in, as shown in the link below.

Web Link

Myoglobin & Meat Color

There are a number of enzymes that use iron as a cofactor. We've already talked about two in this class.

Iron is a cofactor for the antioxidant enzyme, catalase, that converts hydrogen peroxide to water, as shown below.

Figure 12.731 Catalase uses iron as a cofactor

Iron is also a cofactor for proline and lysyl hydroxylases that are important in collagen cross-linking. This will be discussed further in the vitamin C section. The function of these enzymes is shown below.

Figure 12.732 Importance of ascorbic acid and iron to proline and lysyl hydroxylases.

Heme iron is also found in cytochromes, like cytochrome c in the electron transport chain as shown below1.

Figure 12.733 Cytochrome c in the electron transport chain contains iron2

References & Links

1. Gropper SS, Smith JL, Groff JL. (2008) Advanced nutrition and human metabolism. Belmont, CA: Wadsworth Publishing.

2. http://wikidoc.org/index.php/File:ETC.PNG