Binding of oxygen to myoglobin and hemoglobin

Biochemical equihbria can be far more complex than those we have considered so far, but exactly the same principles apply. An example of a complex process is the binding of O2 by hemoglobin in blood, which is described only approximately by reaction B. The protein myoglobin (Mb, Atlas PIO) stores O2 in muscle, and the protein hemoglobin (Hb, Atlas P7) transports O2 in blood. These two proteins are related, for hemoglobin is a tetramer of four myoglobin-like molecules. In each protein, the O2 molecule attaches to ui iron ion in a heme group (Atlas R2) (Fig. 4.8). 

To develop an expression for s, we express [Hb(02)2] in terms of [HbOj] by using K2, then express [Hb02] in terms of [Hb] by using ffi, and likewise for all the other concentrations of Hb(02)3 and Hb(02)4. It follows that 

Because each Hb molecule has four sites at which O2 can attach, the fractional saturation is 

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Case study 4.1 Binding of oxygen to myoglobin and hemoglobin 144... 

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