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Updated: Jul 17, 2026

Measurement of Heme Synthesis Levels in Mammalian Cells
Published on: July 9, 2015
Ferryl haem protonation gates peroxidatic reactivity in globins
Radu Silaghi-Dumitrescu1, Brandon J Reeder, Peter Nicholls
1Department of Biological Sciences, University of Essex, Colchester CO4 3SQ, UK.
Abstract:
Ferryl (Fe(IV)=O) species are involved in key enzymatic processes with direct biomedical relevance; among others, the uncontrolled reactivities of ferryl Mb (myoglobin) and Hb (haemoglobin) have been reported to be central to the pathology of rhabdomyolysis and subarachnoid haemorrhage. Rapid-scan stopped-flow methods have been used to monitor the spectra of the ferryl species in Mb and Hb as a function of pH. The ferryl forms of both proteins display an optical transition with pK approximately 4.7, and this is assigned to protonation of the ferryl species itself. We also demonstrate for the first time a direct correlation between Hb/Mb ferryl reactivity and ferryl protonation status, simultaneously informing on chemical mechanism and toxicity and with broader biochemical implications.
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