Porphyrins Flashcards
Two anatomical sites in the body where porphyrins are synthesized
- Marrow of long bones
- Liver
Chemical structure of heme (# f pyrrole rings and the valence of iron)
Tetrapyrole ring (4 rings) w/ alpha/beta chains and iron w/ a 2+ valence
What is the most common porphyria?
Porphyria cutanea tarda
Enzyme deficiency in porphyria cutanea tarda
Uroporphyrinogen decarboxylase
Enzyme deficiency in acute intermittent porphyria
Porphobilinogen (PBG) deaminase
Enzyme deficiency in congenital erythropoietic porphyria
Uroporphyrinogen III cosynthase
Enzym deficiency resulting in erythropoietic protoporphyria; the enzyme necessary for the incorporation of iron in protoporphyrin X
Ferrochelatase
Porphyrinogens (reduced porphyrins)
- Relative stability
- Color
- Fluorescent properties
- Relative stability: unstable
- Color: colorless
- Fluorescent properties: non-fluorescent
Porphyrins
- Relative stability
- Color
- Fluorescent properties
- Relative stability: stable
- Color: colored (dark red or purple)
- Fluorescent properties: fluorescent (excite at 420nm; emission at 620nm)
What is the reagent used in the porphyrin screening test?
Ehrlich’s reagent
What is the best method for quantitative porphyrin assays?
Liquid Chromatography (LC) or LC/MS
3 most common porphyrias
- Acute intermittent porphyria
- Porphyria cutanea tarda
- Erythropoietic porphyria/protoporphyria
Acute intermittent porphyria
- 1 typical symptom
Acute abdominal pain
Acute intermittent porphyria
- Exacerbating factors
- Drugs/alcohol
- Fasting/dieting
- Oral contraceptives
Acute intermittent porphyria
- Porphyrin that is increased
Porphobilinogen (PBG)