L10-11 Flashcards
(29 cards)
What is the Bohr effect?
Increase in CO2 in blood, decreases in pH and increases unloading of O2
Describe haemoglobin in regards to its subunits
A dimer of two aB protomers NOT tetramer
Describe Immunoglobulin Gs (IgGs) in regards to its subunits
2 heavy chains, 2 light chains
In IgGs, where is the variable region?
At the end of each light chain. They undergo conformational change.
What state is deoxyhaemoglobin in? Position of His HC3? Affinity?
T, Outside, Low
What state is oxyhaemoglobin in? Position of His HC3? Affinity?
R, Inside, High
Myoglobin is __% a-helix
70%
What does theta stand for in regards to the percentage saturation graph for Myoglobin?
No. of sites bound over total sites. It is a fractional saturation of all binding sites on P.
In Myoglobin, where does O2 bind?
Fe2+
Kf/Kb =
Ka
Relationship between Ka and Kd
Kd = 1/Ka
What is theta in regards to binding equilibria?
Theta = L/ Kd + L
When theta = 0.5, L =?
Kd
When theta = 0.9, L = ?
9Kd
O2 binding causing heme group to become more ____
planar
Hill coefficient, nH indicates?
The interaction between the binding sites
Increase in acid, CO2, 2,3- BPG leads to?
decrease in affinity, decrease in O2 loading
Cooperative binding, concerted model is?
All-or-none, either T or R
Cooperative binding, sequential model is?
A change in one L affects another one
Where does H+ bind on Hb? (3)
N-termni of the a subunits, His146/His HC3 of the B subunits and other AA residues
Hb transports ___% of tissue H+ and up to __% of tissue CO2 to the lungs and kidneys
40, 20
Where does CO2 bind on Hb?
Binds as carbamate to amino terminal NH2 of each subunit to form COO-NH-CHR…in a reaction that produces H+
Hb has a single binding site for BPG at the centre which is larger in the _ state
T
Difference in foetal Hb to adult Hb that allows it to have a lower affinity for BPG and higher affinity for O2?
Gamma instead of beta subunits
