Monday, September 20, 2010

Figure 9.10

Figure 9.10 on page 377 is very significant. This figure shows the saturation curve of haemoglobin as it moves from low oxygen concentration to high.

This is a great example of the cooperativity effect, particularly in proteins.

It is also biologically relevant, concerning a process that occurs while we breathe.

It can relate information on the structure of haemoglobin without the use of imaging techniques. As fitting the data estimates that haemoglobin is made up of more than one oxygen-binding subunit, which is in fact true.

1 comment:

  1. This was quite an interesting topic to read up on. As it was, there were two significant people involved in this discovery. We have C. Bohr (father of N. Bohr) who managed to show this sigmoidal curve, and A. Hill, who found the best number of binding sites to describe myoglobin and hemoglobin. What Hill's model relied on though was an all-or-nothin binding situation, which was later rectified by G. Adair. Adair managed to establish that hemoglobin is a tetramer, four subunits resembling a single myoglobin. The binding of oxygen to this sites is seen to be highly cooperative, but is not really an all-or-nothing situation (since the effective value of n is less than the actual number of binding sites), but more of a "if you bind one, you'd better bind more" type deal.