Characterization of the selective alkylation site in hemoglobin A by dihydroartemisinin with tandem mass spectrometry

•The reaction between dihydroartemisinin (DHA) and hemoglobin A (HbA) was investigated in vitro.•Fluorescent HbA-artemisinin adducts were visualized on SDS-PAGE.•DHA selectively modified HbA at βTyr35 as revealed by mass spectrometry.

The reaction between the antimalarial drug dihydroartemisinin (DHA) and hemoglobin A (HbA) was investigated in vitro. A fluorescein-tagged artemisinin analog reacted with HbA and fluorescent HbA-drug adducts could be visualized on SDS-PAGE to confirm stable covalent reaction adducts and necessity of the endoperoxide moiety and Fe(II). Mass spectrometric analyses revealed that DHA favourably alkylated protein part rather than heme and the modification site was identified to be at Tyr35 of the beta globin chain.

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