Which essential biochemical pathway is inhibited by toxic Lead (Pb), leading to microcytic anemia in lead poisoning? (Hard)
Answer and explanation
Correct answer: A. Heme biosynthesis via inhibition of delta-aminolevulinic acid dehydratase and ferrochelatase
- Step 1: Lead binds tightly to sulfhydryl groups of key enzymes in the heme synthetic pathway. Step 2. It inhibits delta-aminolevulinic acid dehydratase (ALAD) and ferrochelatase, preventing iron incorporation into protoporphyrin IX and causing basophilic stippling and anemia. Answer: Heme biosynthesis via inhibition of delta-aminolevulinic acid dehydratase and ferrochelatase. Why not the others: Hexokinase is not primary lead target; ATP synthase is not specific lead target; RNA polymerase is not inhibited primarily.
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