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| therm box |
-cooperativity of oxygen binding for Hb.
-increases greatly |
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mcs5109 Thu, 23 Oct 2008 15:27:06 GMT |
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| T to R |
opens up the b subunit so that O2 has greater access to the heme. |
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mcs5109 Thu, 23 Oct 2008 15:26:39 GMT |
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| R state |
OxyHb is R state (reduced) |
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mcs5109 Thu, 23 Oct 2008 15:26:39 GMT |
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| T state |
deoxyHb is T state
-salt bridges formed bw a and b subunits |
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mcs5109 Thu, 23 Oct 2008 15:26:39 GMT |
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| distal histidine |
-O2 binding to heme is bent
-CO bind is stright
-distal histidine prevents CO from binding to heme |
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mcs5109 Thu, 23 Oct 2008 15:26:39 GMT |
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| fetal hemeglobin |
a2g2
BPG is same concentration in fetal erythrocytes as maternal but has lower affinity for HbF. Thus, HbF binds oxygen with greater affinity |
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mcs5109 Thu, 23 Oct 2008 15:20:37 GMT |
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| higher alt |
more BPG
-BPG is synthesized in erythrocytes and cannot diffuse out |
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mcs5109 Thu, 23 Oct 2008 15:20:36 GMT |
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| BPG |
-favors formation of deoxyHb
-important in that arterial blood to release O2 |
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mcs5109 Thu, 23 Oct 2008 15:18:04 GMT |
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| stripped = 1st |
-higher affinity than whole blood
-b/c of BPG |
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mcs5109 Thu, 23 Oct 2008 15:18:04 GMT |
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| deoxy heme |
Deoxy binds more CO2 than oxyHb |
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mcs5109 Thu, 23 Oct 2008 15:18:04 GMT |
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| Bohr effect |
-based on pH
-pO2 is low in capillaries and the H+ generated by carbonic anhydrase drives the O2 off of Hb facilitating its release
-opposite in lungs
-capillaries= acidic |
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mcs5109 Thu, 23 Oct 2008 15:14:40 GMT |
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| picket fence |
-Picket fence prevented formation of two hemes with O2 as the bridge.
Picket fence describes how the globin molecule surrounds the heme and prevents autoxidation.
-2 O's can't contact each other |
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mcs5109 Thu, 23 Oct 2008 15:14:40 GMT |
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| Hill coeffient |
-n= Hill constant.
-if n=1, then binding curve is hyperbolic and is said to be noncooperative
-if n>1 the it is positively cooperative (Hb curve)
-if n<1, then it is negative cooperativity (Ligand binding reduces affinity of the next ligand) |
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mcs5109 Thu, 23 Oct 2008 15:14:40 GMT |
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| myoglobin curve |
-sigmoidal
-binding of myoglobin almost 0 in venous pressure |
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mcs5109 Thu, 23 Oct 2008 15:14:39 GMT |
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| MetMb reductase |
-reduced MetMb |
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mcs5109 Thu, 23 Oct 2008 15:04:27 GMT |
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| NO |
-vasodilator
-removed my myoglobin once vessels vasodilated
-yields nitrate and MetMb |
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mcs5109 Thu, 23 Oct 2008 15:04:27 GMT |
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| Methhemoglobin reductase |
-reduced hemoglobin to +2 |
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mcs5109 Thu, 23 Oct 2008 15:04:27 GMT |
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| Fe+2 |
-Fe required for O2 binding
-color changes from purple to scarlet
-oxidized Hb= Met Hb |
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mcs5109 Thu, 23 Oct 2008 15:04:27 GMT |
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| heme |
-Mb and each subunit of Hb has one heme.
-also found in cytochromes, cytochrome P450
-Contains 4 pyrrole rings. Has His as one of the ligands and an open 6th axial coordination position for O2 to bind. |
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mcs5109 Thu, 23 Oct 2008 15:01:48 GMT |
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| low temps |
increased O2
no need for hemoglobin in arctic fish |
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mcs5109 Thu, 23 Oct 2008 15:01:48 GMT |
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| myoglobin |
-agent to transport O2 in muscle |
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mcs5109 Thu, 23 Oct 2008 15:01:48 GMT |
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| hemoglobin |
-a2b2
-related to myoglobin (Mb)
-gets O2 to larger organisms |
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mcs5109 Thu, 23 Oct 2008 15:01:48 GMT |
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