MCB Lec 12

red blood cell protein
- tetramer with two alpha and two beta subunits
- an allosteric protien

a single polypetide chain
- binding of O2 NOT cooperative
- binds to oxygen in muscle cells

more

Cooperativity enhances oxygen delivery by hemoglobin
so that even though it doesnt pick up more O2 it delivers more O2 than myoglobin

the position of the iron atom so the residues of aa can hit conformation angles

consists protoporphyrin and a central iron ion in the ferrous (Fe2+) form, the only form that can bind oxygen.

- bind oxygen in heme groups

occupied by an imidazole ring of a histidine

binds O2

changes the electronic structure of iron making its magnetic properties change
deoxyhemoglobin> oxohemoglobin

can distinguish the relative amounts of oxy- and deoxyhemoglobin.

which corresponds to the T state of allosteric enzymes
- the two ab dimers are linked by an extensive interface.

by pulling the four subunits of the T state closer changing them into the R state when they get closer (15 degrees)

allosteric regulator
- determines the oxygen affinity of hemoglobin
- binding decreases hemoglobin affinity for O2

stabalizes T-state and facilitates the release of oxygen

does not bind to BPG as well so has higher affinity for oxygen

produces more oxygen via the Bohr effect

promotes O2 to release from hemoglobin

Hemoglobin, this is why carbon monoxide poising is dangerous because the hemeglobin more readily uptakes CO2 than O2, treated via hyperbaric oxygen therapy

causer by a mutation in hemoglobin (glu--> val)
making it harder to produce more iron, the patch will polymerize and create a hydrophobic region

fewer red blood cells and less functional hemoglobin

The a chain is not produced in sufficient quantity making the hemoglobin have a lower affinity with O2

the b-chain is not produced in sufficent quantity making hemoglobin insoluble

alpha-hemoglobin stabilizing protein

indicates cooperativity
• n > 1: positive cooperativity: binding at one site increases the binding at
other site(s).
• n = 1: no cooperativity: binding at each site is independent
• N < 1: negative cooperativity: binding at one site decreases the binding at
other site(s).