What is a ligand?
Anything that is bound by a protein. It can be another molecule or a whole different protein.
What is induced fit?
When the binding of a ligand causes a conformational change in the protein. It can change the properties and function of the protein.
Myoglobin and Hemoglobin roles
Myoglobin: Tertiary protein that LOVES oxygen and facilitates oxygen storage in muscle tissue
Hemoglobin: Quaternary structure found in red blood cells that transport oxygen from lungs to muscles.
With a single heme group, myoglobin can bind __ oxygen molecule(s)
1
With four heme groups, Hemoglobin can bind __ oxygen molecule(s)
4
Does hemoglobin or myoglobin have a greater affinity for oxygen?
Myoglobin
Myoglobin is a small globular protein consisting of:
-A single polypeptide of 153 residues arranged in eight α-helices.
and
-A heme group.
What does oxygen function as inside the protein hemoglobin
The ligand
What is the difference between T state and R state hemoglobin structures
T state- Deoxyhemoglobin (No oxygen)
R state- Oxyhemoglobin (yummy oxygen)
-They are in rapid equilibrium.
When the normal ligand and modulator are the same, the interaction is…
Homotropic
When the modulator is different from the normal ligand the interaction is…
heterotropic
In hemoglobin and myoglobin, what do allosteric activators and inhibitors stabilize?
-Allosteric activators (like O₂) stabilize the R (relaxed) state, which has high oxygen affinity.
-Allosteric inhibitors (like CO₂, H⁺, and 2,3-BPG) stabilize the T (tense) state, which has low oxygen affinity.
What does oxygen serve as for hemoglobin in ligand and allosteric terms?
Homotropic allosteric activator
2,3 Bisphosphoglycerate is a heterotropic allosteric inhibitor of _________
Hemoglobin
How does increased 2,3-BPG affect hemoglobin’s oxygen affinity?
Increased 2,3-BPG decreases hemoglobin’s O₂ affinity, stabilizing the T state.
What is the bohr effect?
The Bohr Effect describes the pH
dependence of hemoglobin’s affinity of O2
-Hemoglobin has a lower affinity for O2
at decreased pH
CO2 linkages causes Hemoglobin to have a greater or lesser affinity for oxygen?
LESSER
Hemocyanin and Hemoglobin are similar because…
They both utilize their heme groups and use histidine to bond with a transition metal. Hemocyanin uses copper and Hemoglobin uses iron.
