Mnemonic: Stupid Girls Always Pick Bad Uses Concerning Preventing Pregancy Heme
Requires pyridoxal phosphate as a cofactor!
Rate limiting step, occurs in mitochondria
Major regulatory step
When we create ALA (5 carbon structure) we lose CoA and a CO2
Heavy metals inhibit ALA dehydrase
Occurs in cytoplasm
Characteristic of lead poisoning is the elevation of ALA in the absence of an elevation of porphobilinogen because it inhibits ALA dehydrase
Uroporphyrinogen III: AP, AP, AP, PA!!!
Occurs in cytoplasm. Lose 4 CO2 All of the acetyls on the Uro'gen III become methyls!! Though copro'gen III exhibits resonance features within each pyrrole ring, they do NOT demonstrate resonance b/t pyrrole groups. Thus, they are unstable and readily oxidized to porphyrins.
Treatment with interferon/ribavirin and regular phlebotomy to reduce hepatic iron can improve clinical outcome
c. Iron Overload!!
Excess iron leads to the formation to the formation of oxygen species which can inhibit urogen decarboxylase
d. HIV infection