Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
27 Cards in this Set
- Front
- Back
|
What does glutathione reductase do?
substrate? product? |
This reduces glutathion from its dimerized S-S form, to G-SH.
It turns NADHP-->NAHD |
|
|
What does glutathione peroxidase do?
|
This uses Reduced glutatione G-SH to neutralize H2O2
|
|
|
What is G6PD deficiency? general-
|
This the inability to create the HMP shunt, as G6PD is the rate limiting enzyme of the HMP shunt's oxidization branch
|
|
|
What conditions would expose G6PD deficiency?
|
Oxidative stress, Bactrim, Fava beans, infections
|
|
|
What does oxidative stress do to RBCs?
|
This destroys their cytoskeleton (H2O2 accumulation) and causes hemolytic anemia
|
|
|
Is there any advantage of G6PD deficiency?
|
It may confer malaria resistance
|
|
|
What are the CBC findings in someone with hemolytic anemia?
|
Low RBC, Low HGB Low HCT levels.
High reticulocytes. |
|
|
If less NADPH is being formed by HMP shunt, how does the affect H2O2 levels in blood?
|
People with G6PD cannot produce adequate NADPH under stress. So no NADPH, no Glutatione reduction, no H2O2 reduction!
|
|
|
What are the sources of NADPH in the body?
|
Malic enzyme and HMP shunt (oxidative branch)
|
|
|
Why does hemolytic anemia only affect RBCs?
|
they have no mitochondria to help produce NADPH with malic enzyme
|
|
|
What are the two main causes of hemlytic anemia? which one is by far the most common?
|
MOST COMMON- G6PD issues
distant second- Pyruvate Kinase defective |
|
|
How does pyruvate kinase failure cause hemolytic anemia?
|
This leads to overall ATP production reduced in RBC's, This affects Na+/K+ ATPase and biosynthesis of glutathione.
leads to high levels of H2O2 |
|
|
How does G6PD affect glutathione concrentration? PK deficiency?
|
G6PD does not, PK decreases it
|
|
|
Which one affects glutathione production, which one affects glutathione regeneration? G6PD or PK?
|
G6PD affects glutathione regeneration,
PK affects glutathion production |
|
|
How do RBC's compensate for low Hb?
|
Increase 2,3 BPG!
|
|
|
What is cyanosis?
|
This is an increase in methemoglobin (greater than 10%)
|
|
|
Which cytochrome is involved in methemoglobin conversion?
|
B5
|
|
|
What converts methemoglobin to hemoglobin?
|
Cytochrome B5 oxidase
|
|
|
What form of cytochrome b5 is needed to convert methemoglobin to hemoglobin? what makes it?
|
the reduced form of b5, made by cytochrome b5 reductase (using NADH)
|
|
|
What kinds of compounds can produce methemoglobin?
|
nitrites, or nitrates or auto
|
|
|
How does methylene blue work?
|
This use NADPH to convert MetHb to Hb.
|
|
|
How is ethanol broken down in cytosol? what does it make ALOT of?
|
It is broken down in cytosol using alcohol dehydrogenase, it generates LOTS of NADH.
Also aldehyde dehydrogenase produces lots of NADH too (next step) |
|
|
How is ethanol broken down in SER? what does it consume alot of?
|
In the SER, ethanol is broken down by a P450 enzyme...this consumes alot of NADPH!
|
|
|
How is NAD+ regenerated in an alcoholic liver?
|
OAA-> Malate by Malate shuttle
Pyruvate-> lactate by LDH Glycerol 3-P shuttle |
|
|
What is a consequence of High NAD+ in liver of an alcoholic?
|
it consumes OAA/Pyruvate, which were needed in gluconeogenesis
|
|
|
What is thiamine a precursor for? What enzyme uses it?
|
TPP, PDHC
|
|
|
What is caused by decreased PDHC activity?
|
an accumulation of pyruvate, shunted to OAA or lactate
|
