Heme Synthesis D/O

Question 1

Rate limiting step of heme synthesis

Answer 1

delta-aminolevulinic acid synthase w/cofactor Vit B6

• converts glycine+succinyl-CoA into delta-aminolevulinic acid

Question 2

Lead poisoning affects what enzyme

Answer 2

ferrochelatase and ALA dehydratase

Question 3

accumulated substrate in lead poisoning

Answer 3

protoporphyrin and delta-ALA

Question 4

acute intermittent porphyria affects what enzyme

Answer 4

porphobilinogen deaminase

Question 5

accumulated substrate in acute intermittent porphyria

Answer 5

porphbilinogen
delta-ALA

copophobilinogen in the urine

Question 6

5P’s of acute intermittent porphyria

Answer 6

1. painful abdomen
2. port wine-colored urine
3. polyneuropathy
4. psych disturbances
5. precipitated by EtOH, drugs, starvation

Question 7

porphyria cutanea tarda affects what enzyme

Answer 7

uropophyrinogen decarboxyalse

Question 8

accumulated substrate in porphyria cutanea tarda

Answer 8

uroporphyrin (tea-colored urine)