Biochem Ch4-5
An antibody binds an antigen with a Kd of 5x10-8M, at what antigen concentration will Θ= 0.8?
(2 x 10-7 M.. Θ= L/ L+Kd means L= (Θ/(1- Θ))*Kd===0.8/0.2=4, 4*5x10-8M ==2 x 10-7 M)
An antibody binds an antigen with a Kd of 5x10-8M, at what antigen concentration will Θ= 0.5?
(5x10-8M .. Θ= L/ L+Kd means L= (Θ/(1- Θ))*Kd===0.5/0.5=1, 1*5x10-8M ==5x10-8M)
What fraction of known (parts of) proteins are intrinsically Disordered?
1/3
For a protein to have quaternary structure, it must have...
2 or more subunits
Say an antibody binds an antigen with a Kd of 5 x 10-8M, what fraction of the binding sites will be occupied at the antigen concentration of 1.25 x 10-8?
20% (Θ= L/ L+Kd =1.25/1.25+5= 1.25/6.25=20%)
Binding of CO by free heme is how much stronger than O2 by free heme?
20,000x stronger
The collagen superhelix has how many helices and is which handed?
3 helices, right-handed
At an antigen concentration of 2.5 x 10-8M, what fraction of the binding sites will be occupied?
33% (Θ= L/ L+Kd ==2/ 2+4 ==2/6=1/3=33%)
Binding of CO by heme in Myoglobin is how much stronger than O2 by heme in Myoglobin?
40x stronger
Say an antibody binds an antigen with a Kd of 5 x 10-8 M, at what antigen concentration will half of the antibody binding sites be occupied?
5 x 10-8 M (Kd IS when half the binding sites are occupied)
How many bonds can the Fe2+ ion at the center of the heme group form?
6
Alpha-keratin includes...
A left-hand super helix
The alpha chain of collagen is...
A left-handed helix
The bond between the C and N atom in the peptide bond is...
A partial double bond
When CO2 increases, the affinity of Hb for O2...
Decreases
When the BPG increases, the affinity of Hb for O2...
Decreases
Alpha-keratin includes...
Disulfide cross-links
An example of quaternary structure is...
Hemoglobin
Where is the affinity of Hb for O2 the HIGHEST, peripheral tissue or lungs, top of Mt Everest or Sea level?
In the lungs, at Sea Level
When the pH increases, the affinity of Hb for O2...
Increases
How is the affinity of Hb for O2 related to the amount of H+ and CO2 bound?
Inversely proportional (the Bohr Effect) High H+ and high CO2 =low O2 affinity; Low H+ and low CO2 =high O2 affinity
Collection of 2 or more secondary structure elements is a...
Motif
Where is the affinity of Hb for O2 the LOWEST, peripheral tissue or lungs, top of Mt Everest or Sea level?
Peripheral tissue, on the top of Mt. Everest
Structure of the peptide bond, how many atoms?
Planar, 6 atoms
Vitamin C is required to form collagen, by converting what to what?
Proline to hydroxyproline
Alpha-keratin DOES NOT include...
Right hand super helices
The melting temperature of a protein is the temperature at which...
The protein is 50% unfolded
Alpha-keratin includes...
a right-hand helices