2.12-Hemo&MyoGlobin Flashcards
What is the Bohr effect?
Effects of CO2 and H+ on HemoGlobin
Does cooperatively work in hemoglobin or myoglobin? Or both?
Hemoglobin only
What type of oxygen binding curve does Hemoglobin have? What Partial Pressure does it bind at?
Sigmoidal. Binds at 26 torr
What type of oxygen binding curve does Myoglobin have?
Hyperbolic
What is the structure of hemoglobin? hint: how many dimers..etc
Its a TETRAMER composed of two Alpha-Beta Dimers
What are the __3__ methods to get CO2 from the tissues to the lungs? Whats the major way?
Dissolved CO2 in blood, Carbamino-hemoglobin, and bicarb… Bicarb is MAJOR way, 14% Carbamate
What 3 signalers facilitate the release of oxygen from hemoglobin?
Increase H+, Increased CO2, and Increased 2,3BPG…Think cell that is working hard needs more O2!!
Which form of hemoglobin can be used to monitor long-term blood glucose control in diabetics?
Hemoglobin A1c
What is the RATE LIMITING step in Heme Synthesis? What is the enzyme used? What Coenzyme is used?
Succunyl-CoA + Glyceine = DALA.. Enzyme:DALA Synthase COenzyme: Pyridoxal phosphate DALA DALA BILLS YO
Where are the two main locations of Heme synthesis?
Bone marrow and liver
What type of rings comprise the active sight of heme and myoglobin? Which ion form of iron is in the center?
4 Pyrrole (5C) rings; Fe2+
What is myglobin made from? How many alpha helices? What keeps the O2 in?
One polypeptide chain and 8 alpha helices..A distal and a proximal histidine keep the oxygen in
When does myoglobin have the highest affinity for oxygen? What Partial Pressure?
At LOW [O2] (2 torr). Its like a sponge for muscle cells
What is the most common form of Hemoglobin in adults?
Hb A
What type of hemoglobin has a higher affinity for O2 and therefore is genetically stimulated for sickle cell anemia pts?
Hb F (Fetal hemoglobin)
Is hemoglobin considered hydrophilic or hydrophobic?
Hydrophobic, even though it has H bonds and ionic pairs!
Which formation has a LOW affinity for O2? T or R?
Taut (release oxygen)
Which formation has a HIGH affinity for O2? T or R?
Relaxed (pick up oxygen)
What is the degree of difference between T and R?
15 degrees
When oxygen binds to iron II does the active site go into the plane of the molecule or go out of the plane of the molecule?
It goes into the plane
Why would high 2,3BPG increase hemoglobin release of oxygen? Which state does it put hemoglobin in? R or T?
2,3BPG is a byproduct of glycolysis. The cell is working hard and needs oxygen. T=taut=low O2 affinity=release of O2
What about the structure of Fetal hemoglobin causes more O2 affinity? What about 2,3 BPG?
Because it has two alpha and two GAMMA subunits it does not bind 2,3 BPG as well. NO 2,3 BPG=NO T formation=Less release of O2
How much of a pH difference causes an 11% difference in O2 release?
7.4 to 7.2 pH causes hemoglobin to release 11% more O2
Does CO2 compete with O2 for binding sites on hemoglobin?
NO!
