Chapter 7: Protein Function: Myoglobin and Hemoglobin, Muscle Contraction, and Antibodies Flashcards
(48 cards)
exhibits a hyperbolic O2-binding curve.
Myoglobin
can adopt the deoxy (T) or oxy (R) conformation
Hemoglobin
triggers conformational changes in hemoglobin
oxygen binding
why does oxygen binding trigger conformational changes in hemoglobin
so that oxygen binds to the protein cooperatively, yielding a sigmoidal binding curve.
alter hemoglobin’s O2-binding affinity.
Bohr effect and BPG
has low affinity for oxygen
hemoglobin
has high affinity for oxygen
myoglobin
what has better oxygen delivery hemoglobin or myoglobin
hemoglobin
prevents this oxidation and makes it possible for O2 to bind reversibly to the heme group
The protein portion of myoglobin and hemoglobin
CO has what affinity for hemoglobin than does O2.
200-fold greater
its major physiological role is to facilitate oxygen diffusion in muscle.
myoglobin
The rate at which O2 can diffuse from the capillaries to the tissues is limited by its what
low solubility in aqueous solution
which is present mainly in brain, retina, and endocrine tissues
neuroglobin
which occurs in most tissues.
cytoglobin
occurs when ligands interact independently with their binding sites.
hyperbolic binding curve
Animals that are too large (>1 mm thick) for simple diffusion to deliver sufficient oxygen to their tissues have circulatory systems containing what
hemoglobin
what makes hemoglobin a better O2 carrier
high concentration of BPG
High P50
what happens to the BPG concentration in low O2 environments such as in high altitudes
increases
O2 binding to hemoglobin is described by a
sigmoidal (S-shaped) curve
This permits the blood to deliver much more O2 to the tissues
sigmoidal (S-shaped) curve
increases with the degree of cooperativity of a reaction
quantity n, the Hill constant
For normal human hemoglobin, the Hill constant is between
2.8 - 3.0
Oxygen Binding to Hemoglobin Triggers a Conformational Change from what to what
T to R
are conformations of deoxyhemoglobin & oxyhemoglobin respectively
T & R states