Which enzyme controls production of NADPH in pentose phosphate pathway?
Glucose-6-phosphate dehydrogenase (G6PD)
T/F: RBC utilizes oxygen and burn glucose aerobically
False; RBC burns glucose anaerobically because they don’t have nucleus, mitochondria, ribosomes, ER, Golgi, lysosomes, you name it. Its just a bag of hemoglobin and that’s it
Anaerobic metabolism produces ____ ATP per glucose. What are the enzymes that yields ATP in glycolysis (anaerobic)?
2.
Phosphoglycerate kinase
Pyruvate kinase
What is the importance of G6P dehydrogenase?
G6P dehydrogenase is involved in pentose phosphate pathway in making NADPH, which is important in protecting the cell from reactive oxygen species (ROS), without NADPH, cell will die
What happens when there is pyruvate kinase deficiency?
ATP production gets cut in half, as pyruvate kinase is one of the two enzymes that can yield ATP in glycolysis, the other one being phosphoglycerate kinase.
Pyruvate kinase deficiency’s effect on RBC:
RBCs will not have enough ATP to power their most energy demanding activity which is to maintain Na/K ATPases and so will result in osmotic stress and lead to hemolysis and stress
T/F: overall aerobic metabolism is mostly independent of pyruvate kinase in contrast to anaerobic metabolism, even though pyruvate is linked to many other bioprocesses.
True; fatty acid produces acetyl coA and completely bypasses pyruvate kinase, and that can yield energy for cells undergoing aerobic metabolism
NADPH gives its electron and thereby _____ glutathione, and glutathione gives its electron for the ______ of ______
Reduces
reduction
ROS
T/F: liver contains most of the body’s iron and most of the body’s oxygen storage
False and false; RBC contains most of the body’s iron and oxygen
Ferrous is Fe ___, and ferric is Fe ___. Which is the iron in hemoglobin?
2+
3+
In hemoglobin, the iron is in 2+ oxidation state = ferrous
Deoxyhemoglyobin must have iron in ____ state in order to bind O2. Upon binding to O2, the Iron losses its electron to oxygen to become ____. Upon releasing the O2, the electron usually remains with ____ and that heme will be able to bind another O2
2+
Fe3+
Iron (so iron goes back to Fe2+)
How is Metheomglobin formed? How is it fixed?
When the oxygen that is leaving the hemoglobin kept its electron, and left as a superoxide radical and leaves a Fe3+ behind, this is methemoglobin and it is nonfunctional.
To fix the methemoglobin back to its function deoxyhemoglobim, use high energy electron from NADH and methemoglobin reductase
Superoxide is reduced to hydrogen peroxide by ______. And hydrogen peroxide is reduced to water by ______. Glutathione must be regenerated from ______ by _____
Superoxide dismutase
Glutathione peroxidase
NADPH
Glutathione reductase
What is the precursor to glutathione? (glutathione is relevant in reducing ROS)
Glutamate
T/F: For RBCs, NADH is oxidized back to NAD+ so that glycolysis can continue, but it also plays a role in converting pyruvate into lactate, as well as converting methemoglobin (nonfunctional) into deoxyhemoglobin (functional waiting for O2 to bind)
True
NADH gives its electron to ______ and lactate dehydrogenase converts it to ______.