BIOC 3560 Lecture 5: biochem PACK FIVE.pdf
3 Dec 2014
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Document Summary
2 important ion pairs in hb are formed between his. Hc3 of the subunit and both asp fg1 of the subunit and lys c5 of the subunit. Ion pairs at the 2 1 and 1 2 interfaces of deoxy-hb result from the 3-dimensional conformation of the protein. Hb binds o2 efficiently in the lungs and releases it easily in peripheral tissues. Hb undergoes conformational change low affinity high affinity. O2 binding to one subunit of hb alters the affinity for o2 in adjacent subunits. Induced conformational changes push adjacent subunits into the r state. This is a product of hb"s quaternary structure. Allosteric protein: a protein in which the binding of a ligand to one site affects the binding properties at another site. Allosteric modulators homotropic: ligand and modulator are identical heterotropic: ligand and modulator are different. Can be activators (+) or inhibitors (-) for hb: o2 is a ligand and an activating homotropic modulator.
