module 5 Flashcards
(24 cards)
Induced Fit
Changes in conformation that change the properties of a protein which changes its function
Myoglobin
monomeric protein that stores oxygen in tissues
Monomeric Protein
Proteins that combine to form multiple protein complexes
Hemoglobin
Proteins that transport oxygen in red blood cells
Oxygen solubility
Oxygen is hydrophobic
Fe Six coordinating interactions
4 come with the heme rings
5 is an imidazole group of histidine one distal group (top) and one proximal group (bottom)
lastly an O that binds
CO2 Poisoning
CO2’s got a lower affinity than Oxygen which means that Hem and Myo will actually bind to them instead of Oxygen
Myoglobin
Tertiary structure with a heme group
Can bind to 1 oxygen
Hemoglobin
Can bind to 4 oxygen
each subunit resembles a myoglobin
Structure of myoglobin
single polypeptide with 153 residues arranged in 8 alpha helices
a heme group
Oxygen Saturation curve for Myoglobin
3 torr is required to saturate 50% of myoglobin
we have 100 torr of oxygen in the lungs
20 torr in the lowest concentrations
Saturated Oxygen Calculation
x= [pO2] / [pO2]/ [pO2] +[P50]
p50= 3 torr
Partial pressure of O2 in lungs is 100
In peripheral tissue is 20
Hemoglobin Structure
Quaternary structure
contains red blood cells
Allosteric Proteins
(Other structures)
T (inactive) and R (active) forms
T <—> R are in equilibrium
Allosteric Modulators
Bind to allosteric proteins at specific sites
Allosteric activator stabilizes the R
Allosteric inhibitor stabilizes the T
Homotropic
Modulator and Ligand are the same
Heterotropic
Ligand and modulator are different
T to R transition
T state in the iron atom is outside of the heme ring
R state moves iron into plane of heme ring
2,3 Bisphospho-D-glycerate
An inhibitor for decreasing the affinity for oxygen in the hemoglobin
O2 delivery and CO2 removal
CO2 is taken up by red blood cells and converted into bicarbonate and a proton is released
more protons = lower ph
lower pH will release more oxygen to the tissues
O2 delivery and CO2 removal #2
CO2 Links to N terminus of each chain in Hemoglobin to form Carbaminohemoglobin
Carbamino Hemoglobin has lower O2 affinity than hemoglobin to promote O2 release
Protons/ acids
More protons = decreased pH = lower oxygen affinity
Sickle Cell Anemia
Change in single amino acid
Fibers form in capillaries which block blood flow
Hemocyanin
Uses Copper rather than iron to transport oxygen
no heme ring in a group
