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8 Cards in this Set

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What are porphyrins?
Porphyrins are a group of organic ring molecules that serve as cofactors for a number of proteins and enzymes.

Porphyrins are "tetrapyrroles," many of which bind metal ions (such as iron) in the center.
What are the functions of porphyrins?
-oxygen transport: hemo- and myoglobin
-electron transport, respiration
-redox reactions: cytochrome p450 family, catalase: destruction of peroxide
-other reactions: nitric oxide synthase
Which porphyrias are nonfluorescent?
Porphyrias with Fe, Pb
What is the first step in porphyrin biosynthesis?
5-ALA synthase condenses succinyl-Co + glycine yield make ALA (δ-aminolevulinate)
What does a deficiency of erythroid ALAS2 cause?
XLSA, S-linked Sideroblastic Anemia
What is the second step in porphyrin biosynthesis?
Prophobilinogen synthase condenses 8 ALAs to form 4 porphobilinogens.
What causes ALA dehyrdatase deficiency porphyria?
A deficiency of ALAD.
What is the rate controlling step in porphyrin biosynthesis?
The formation of ALA (step 1).