Oxygen carriers, structure-function

Hydrophobic interactions are a major factor in the folding of proteins into the specific three-dimensional structures required for their functioning as enzymes, oxygen carriers, or structural elements. It is known experimentally that proteins tend to be folded so that the nonpolar hydrophobic side chains are sequestered from water in the interior of the protein, while the polar hydrophilic side chains lie on the exterior of the molecule and are accessible to the aqueous environment (Figure 4.33). 

Finally, protein chains interact with each other as subunits associate to make a functional species. For example, hemoglobin, the mammalian oxygen carrier, contains two each of two different subunits. The ability of hemoglobin to deliver oxygen to the tissues is dependent on the association of these subunits. Interaction of proteins to form a multimer composed of several subunits is termed the protein s quaternary structure. Quaternary structure is often very important in determining the regulatory properties of a protein. 

BIOLOGY STRUCTURE, FUNCTION, AND O2 BINDING OF OXYGEN CARRIERS... 

In recent years the rapid development of interest in metal complexes having the ability of uptaking the molecular oxygen has been observed (1-9). It is believed that the elucidation of the properties and structures of these low-molecular activators and oxygen carriers will allow more complete understanding of the role, function, structure and mechanism of action of natural systems which involve the oxygen into biological processes. 

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