Hemoglobin Is an Allosteric Oxygen-Binding Protein

Alternative Theories on How Hemoglobins and Other Allosteric Proteins Work Muscle Is an Aggregate of Proteins Involved in Contraction 

Each protein is exquisitely suited to carry out a specific function. 

N ow that some of the major types of protein structures have been described it is appropriate to turn to the question of how protein structure relates to protein function. To explore this question, two protein systems, hemoglobin and the actin-myosin complex, are examined in detail. 

The heme pocket. The helices of hemoglobin (and myoglobin) form a hydrophobic pocket for the heme and provide an environment where the iron atom reversibly binds oxygen. The chemical structure of heme is shown in figure 5.10 and is described in atomic detail in chapters 10 and 14. (Illustration copyright by Irving Geis. Reprinted by permission.) 

If y is the fraction of myoglobin molecules saturated, and if the oxygen concentration is expressed in terms of the partial pressure of oxygen [02],a then 

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