Solution to PS 3 #7

a) Lys has a positive charge at pH 7 and is involved in binding BPG (which is negatively charged).  Asn has no charge at pH 7.  This means that replacing Lys with Asn would lead to a lower affinity for BPG. This is similar to the case of fetal Hb.

b)  As the BPG affinity is lowered the O2 affinity should increase since the BPG stablizes the deoxy form of Hb.  The relative binding curves predicted are sketched below. This will lead to a less efficient O2 delivery system due to diminished ability of Hb Providence to unload O2 in the tissues.


 


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