Synthesis and Catabolism of Porphyrins

Question 1

all carbons in the porphyrin ring are derived from

Answer 1

Succinyl-CoA amd glycine

Question 2

what is the overal rxn of heme synthesis

Answer 2

8 GLY + 8 succinyl CoA = porphyrin, 8 CO2 + 4 NH4

Question 3

what is the cofactor required for heme synthsis

Answer 3

B6

Question 4

where does heme synthesis span

Answer 4

mitochondria and cytosol

Question 5

heme synthesis negatively regulates itself at the _____ _____ step

Answer 5

ALA synthase

Question 6

heme synthesis requires what three things

Answer 6

glycine, succinyl-CoA, and B6

Question 7

heme synthesis is inhibited by ______

Answer 7

lead

Question 8

Can Fe levels play a role in control of translation of ala synthase mRNA

Answer 8

yes

Question 9

how does heme regulate its own synthesis

Answer 9

• repressing synthesis of ala synthase

- inhibit movement of ala synthase into mitochondria

Question 10

what kind of porphyria is characterized by episodic acute neruovisceral attacks

Answer 10

acute

Question 11

what kind of porphyria is characterized by light sensitive lesions

Answer 11

non-acute

Question 12

what porphyria is associated with a dysfunctional porphobilinnogen deaminase

Answer 12

acute intermittent porphyria

Question 13

what kind of porphyria is associated with a dysfunctional uroporhyrinogen decarboxylase

Answer 13

porphyria cutanea tarda

Question 14

what is the treatment for patients with PCT

Answer 14

reduce skin exposure (most common non-acute)

Question 15

what are the treatments for AIP

Answer 15

hospitalizations, high carb diet, medications that blcok heme synthesis

Question 16

what is heme broken down into

Answer 16

biliverdin and then bilirubin

Question 17

bilirubin-albumin is considered

Answer 17

unconjugated; indirect

Question 18

bilirubin diglucuronide is considered

Answer 18

conjugated; direct

Question 19

a rare neruological condition that occurs in some newborns with severe jaundice

Answer 19

kernicterus

Question 20

what is the name of the serum bilirubin test

Answer 20

van den berghs test

Question 21

how does the liver rid the body of bilirubin

Answer 21

bilirubin is taken up by hepatocytes and secreted into the bile, which is excreted into the intestine

Question 22

increased Tbill causes

Answer 22

jaundice

Question 23

causes of jaundice

Answer 23

increased bilirubin production (hemolytic anemias)
problems with liver
obstruction of bile duct

Question 24

what are possible problems if direct bilirubin is normal

Answer 24

hemolysis, viral hepititis, cirrhosis

Question 25

if direct bilirubin is normal, what do you suspect

Answer 25

bile duct obstruction

Question 26

what wavelength breaks down bilirubin

Answer 26

460-490