The influence of electrostatic interactions on the detection of heme-globin complexes in ESI-MS.
The heme-globin complexes of hemoglobin and myoglobin are investigated in positive-ion mode and negative-ion mode using a nano-ESI source coupled to a quadrupole ion trap MS and an orthogonal time-of-flight MS. The extent of dissociation of these noncovalent complexes upon collisional activation and thus their gas-phase stability is strongly dependent on the polarity of the ESI-MS experiment as well as on the charge of the prosthetic group (ferri-heme [Fe3+-heme]+ vs. ferro-heme [Fe2+-heme]+/-0). The results clearly point to the important role of electrostatic interactions on the gas phase stability of noncovalent complexes and therefore the ion signals observed in ESI-MS experiments.
Schmidt
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A
Instrumentelle Analytische Chemie, Johann Wolfgang Goethe-University Frankfurt/Main, Germany.
Karas
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M
D000818:Animals; D002417:Cattle; D004563:Electrochemistry; D005914:Globins / Q000737:chemistry*; D006418:Heme / Q000737:chemistry*; D006454:Hemoglobins / Q000737:chemistry; D007501:Iron / Q000737:chemistry; D009211:Myoglobin / Q000737:chemistry; D021241:Spectrometry, Mass, Electrospray Ionization
D006454:Hemoglobins; D009211:Myoglobin; D006418:Heme; D005914:Globins; D007501:Iron