Hemoglobin Flashcards
Need how much oxygen per day
500g. Only 4.1mg/L could dissolve without hemoglobin. With 280/L
Myoglobin
Stores O2 for strenuous exercise.
Hemeproteins
Heme is tightly bound prosthetic group. Heme is where oxygen binds.
Heme structure
4 pyrrole rings, with iron bound to N in middle and N of proximal histidine. Has 2 propionate, 2 vinyl, 4 methyl as well
Blood color is red because?
System of double bonds in heme
Erythrocytes
Contain hemoglobin. 120 day lifespan. No nucleus or mitochondria.
Hematocrit
Female-38-46
Male-42-53
Hemoglobin as tetramer
Dimer of dimers. Two alpha and two non alpha. 97% is two alpha two beta.
States of hemoglobin
Tense is when Oxygen unbound. Relaxed with, binds O 300x more tightly.
Hemoglobin conformation change
O2 pulls iron into plane of molecule. Affects neighbors to make more affinity, by pulling on proximal histidine.
P50
Oxygen pressure at which half of heme is oxygenated.
Small changes in pO2
Responded to very well by hemoglobin
2-3 Bisphosphoglycerate
Reduces affinity of heme for O2, releasing oxygen to tissues. Allosteric. Doesn’t work with fetal heme( ser sub for His).
Bohr effect.
Low pH lowers oxygen binding(salt bridge stabilizes deoxyheme). CO2 also lowers affinity.
CO2 transports
Carbonic anhydrase makes CO2 carbonic acid, turns into bicarbonate to lungs, where the process is reversed. All in erythrocytes.
