2.12 Hemoglobin & Myoglobin Flashcards
What is the enzyme of the rate limiting step in heme formation
DALA Synthase
Describe the rate-limiting step in heme formation
Succinyl CoA + Glycine = DALA
What is the coenzyme of DALA Synthase?
Pyridoxal Phosphate (Vitamin B6)
Where does the first step of Heme formation occur?
In the mitochondria of the liver and bone marrow
How is the production of heme regulated?
It is a feedback loop. A rich supply of Heme downregulates the reaction
Why does Hemoglobin participate in cooperative binding and Myoglobin does not?
Hemoglobin has multiple binding sites for O2 compared to Myoglobin’s one binding site.
What is HA1c?
It indicates the effectiveness of long term sugar control
T or F, The R formation is associated with a Low O2 affinity or in other words this formation stimulates release of O2 from Heme
False. T Formation stimulates release of O2 from hemoglobin
Does the binding affinity for O2 in Myoglobin change?
No. It is always constant
What two things make up the Bohr effect
Co2 and pH decrease the affinity of hemoglobin for binding oxygen
What affect does 2,3-BPG have on hemoglobin?
Converts R state conformation to T state conformation which favors oxygen release from Hemoglobin
What three things favor oxygen release from Hemoglobin?
Co2
H+ (pH)
2,3-BPG
What are the effects of smoking on oxygen carrying capacity of hemoglobin?
2,3-BPG is normally degraded before hemoglobin reaches lungs, in smokers, it is found in high concentration in the lungs. This stimulates oxygen release and makes it harder for smokers to gather oxygen.
How does fetal hemoglobin differ from maternal hemoglobin?
Fetal hemoglobin has a higher affinity for oxygen than maternal hemoglobin. This facilitates transfer of oxygen to fetus.
T or F, Excess Heme will shut off its own synthesis
True
