History
Porphyrin compounds containing zinc have been known since the 1930s. They became of more than academic interest with the discovery, in 1974, that ZPP was the major non-heme porphyrin formed in red cells as the result of lead poisoning or iron deficiency.
It was already known at this time that non-heme Protoporphyrin IX levels were elevated in these conditions, but prior investigators had used extraction methods that converted ZPP to unbound Protoporphyrin IX.
The early literature is sometimes confusing, and results are hard to compare without detailed examination of the measurement methods and the conversion factors used to report the results. Reports may refer to Free Erythrocyte Protoporphyrin (FEP) or Erythrocyte Protoporphyrin (EP or EPP). ZPP is also abbreviated ZP and ZnPP. Current practice is tending to measure and report the molar ratio of ZPP to Heme (μmole/mole).
Read more about this topic: Zinc Protoporphyrin
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