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Mass spectrometric studies of cisplatin‐induced changes of hemoglobin
Author(s) -
Mandal Rupasri,
Kalke Robyn,
Li XingFang
Publication year - 2003
Publication title -
rapid communications in mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.528
H-Index - 136
eISSN - 1097-0231
pISSN - 0951-4198
DOI - 10.1002/rcm.1259
Subject(s) - chemistry , cisplatin , chromatography , mass spectrometry , high performance liquid chromatography , hemoglobin , elution , fractionation , inductively coupled plasma mass spectrometry , selected reaction monitoring , tandem mass spectrometry , biochemistry , medicine , surgery , chemotherapy
This study reports on structural changes of hemoglobin (Hb) that were induced by cisplatin binding. Two techniques, nanoelectrospray quadrupole time‐of‐flight mass spectrometry (nanoES‐MS) and high‐performance liquid chromatography with inductively coupled plasma mass spectrometry (HPLC/ICPMS), were developed to facilitate this study. Nanospray MS analyses of cisplatin and Hb reaction mixtures demonstrated that the ion at m/z 616.5, the heme group, increased with an increase of cisplatin concentration, indicating the loss of heme groups from the intact protein. This conclusion was also supported by the increase of cisplatin‐ α or ‐ β complex formation. The change of the Hb‐bound Fe was further investigated by monitoring Fe signals using size‐exclusion HPLC/ICPMS. After incubation with cisplatin at clinically relevant concentrations, under physiological conditions, the amount of Fe bound to Hb was reduced while formation of cisplatin–Hb complexes increased. Flow‐injection ICPMS analysis of the Fe contents in the low molecular weight fraction (<3000 Da) of the reaction mixtures after size fractionation further demonstrated a corresponding increase of Fe with the increase of cisplatin concentrations. HPLC/ICPMS detected three Hb–cisplatin complexes, one of which eluted at the same retention time as Hb while the other two complexes eluted later than Hb. With clinically relevant concentrations of cisplatin (0.05–1.0 μM) and 10 μM of Hb, the concentrations of the Hb–cisplatin complexes were determined in the range 0.1–64 nM. These results, obtained from nanoES‐MS, HPLC/ICPMS, and FIA‐ICPMS, demonstrate that cisplatin binding to Hb resulted in the dissociation of the heme group from the intact protein. Copyright © 2003 John Wiley & Sons, Ltd.