Study BMB 401H Chap 10 Flash Cards

 
Pile Management Card
BMB 401H Chap 10

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-cooperativity of oxygen binding for Hb.
-increases greatly
T to R
opens up the b subunit so that O2 has greater access to the heme.
R state
OxyHb is R state (reduced)
T state
deoxyHb is T state
-salt bridges formed bw a and b subunits
distal histidine
-O2 binding to heme is bent
-CO bind is stright
-distal histidine prevents CO from binding to heme
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
higher alt
more BPG
-BPG is synthesized in erythrocytes and cannot diffuse out
BPG
-favors formation of deoxyHb
-important in that arterial blood to release O2
stripped = 1st
-higher affinity than whole blood
-b/c of BPG
deoxy heme
Deoxy binds more CO2 than oxyHb
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
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
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)
myoglobin curve
-sigmoidal
-binding of myoglobin almost 0 in venous pressure
MetMb reductase
-reduced MetMb
NO
-vasodilator
-removed my myoglobin once vessels vasodilated
-yields nitrate and MetMb
Methhemoglobin reductase
-reduced hemoglobin to +2
Fe+2
-Fe required for O2 binding
-color changes from purple to scarlet
-oxidized Hb= Met Hb
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.
low temps
increased O2
no need for hemoglobin in arctic fish
myoglobin
-agent to transport O2 in muscle
hemoglobin
-a2b2
-related to myoglobin (Mb)
-gets O2 to larger organisms
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