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Updated: Aug 10, 2026

Measurement of Heme Synthesis Levels in Mammalian Cells
Published on: July 9, 2015
The formation of methaemoglobin by 4-aminopropiophenone (PAPP) and 4-(N-hydroxy) aminopropiophenone
T C Marrs1, R H Inns, J E Bright
1Huntingdon Research Centre PLC, Cambs, UK.
Abstract:
Oral dosing of rats with the cyanide antidote 4-aminopropiophenone (PAPP), brought about peak methaemoglobin levels at 15-40 min, but peak levels were attained at at 15-25 min after intravenous dosing. After both oral and intravenous administration at equimolar doses, 4-(N-hydroxy)aminopropiophenone (PHAPP), the putative methaemoglobin-producing metabolite of PAPP, produced higher peak levels of methaemoglobin than PAPP. Plasma from rats injected with PAPP was capable of forming methaemoglobin when added to naive rat erythrocytes. The identity of the metabolite responsible is discussed.
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