Biochemistry Flashcards
What are the 3 final products when heme is complexed with proteins?
Hemoglobin, myoglobin, and the cytochromes.
These are hereditary or acquired conditions of defective heme synthesis that leads to the accumulation of heme precursors.
Porphyrias
To start making heme, we start the recipe with 8 molecules of glycine and 8 molecules of ___________
Succinyl-CoA
Succinyl CoA and glycine combine to form what acid?
δ-aminolevulinic acid (δ-ALA)
Why is δ-ALA synthase important in the synthesis of heme?
It’s the rate limiting step
Which vitamin does δ-ALA require to fxn?
B6
So what type of anemia can result from a B6 deficiency?
microcytic, hypochromatic anemia
“sideroblastic anemia”
After protoporphyrin IX is produced, which metal combines with it, catalyzed by heme synthase?
Fe++
Which 2 substances inhibit δ-ALA synthase? (think negative feedback)
heme and glucose
Lead poisoning inactivates δ-ALA dehydratase, which can lead to an accumulation of what substance?
δ-ALA
A lack of iron or inhibition of ferrochelatase can lead to an accumulation of what heme precursor?
protoporphyrin IX
What are the 2 products of hemoglobin degradation?
heme + globin
hurrrrrrrrrrrrrrrrrrrrrrrrr
What is the product of heme degradation?
bilirubin
this is why bruises turn yellow after being purple, because bilirubin is yellow
Bilirubin is first converted to what substance before being excreted in the bile?
it’s conjugated to glucuronic acid
This is where heme is degraded to biliverdin.
Macrophage
This is where albumin complexes with unconjugated bilirubin.
Blood
This is where UDP-glucuronate conjugates heme into bilirubin digluconide to be excreted in the bile.
Liver
This is where bacteria deconjugate bilirubin and convert it into urobilinogen.
Gut
20% of this heme degredation product is absorbed into the blood and excreted in the urine, and 80% is oxidized and exreted int eh feces.
Urobilinogen
