title: Evidence for a novel heme adduct generated by the in vitro reaction of 2,4,6-trinitrotoluene with human hemoglobin using electrospray ionization mass spectrometry.
abstract: The bioactivation of nitroaromatic compounds to highly reactive intermediates is responsible for the genotoxic and cytotoxic effects by reaction with DNA and proteins. Due to its continued use as a secondary explosive and its prevalence at contaminated sites, the mechanism of covalent binding of 2,4,6-trinitrotoluene (TNT), or its metabolites, to critical cellular proteins has been of interest. Herein, we report the in vitro reaction of TNT with human hemoglobin under anaerobic and reductive (using sodium hydrosulfite) conditions, yielding a novel adduct between a putative nitrosodinitrotoluene (MW = 211 Da) and the prosthetic heme group (iron protoporphyrin-IX or heme b). While the covalent modification of hemoglobin polypeptide chains by TNT has been established, to our knowledge, this is the first example of a heme-TNT related adduct. This finding could be of relevance in investigation of biotransformation of TNT in subjects exposed to TNT via skin exposure or inhalation.
authors.affiliation: Department of Drug Metabolism, Merck Research Laboratories, Rahway, New Jersey, USA. rbakhtia@stevens-tech.edu
authors.forename: R
authors.initials: R
authors.lastname: Bakhtiar
authors.forename: K H
authors.initials: KH
authors.lastname: Leung
authors.forename: R A
authors.initials: RA
authors.lastname: Stearns
authors.forename: C E
authors.initials: CE
authors.lastname: Hop
mesh_terms: D006418:Heme / Q000737:chemistry*; D006454:Hemoglobins / Q000737:chemistry*; D006801:Humans; D007501:Iron / Q000737:chemistry; D013058:Mass Spectrometry / Q000379:methods*; D009251:NADPH-Ferrihemoprotein Reductase / Q000378:metabolism; D011524:Protoporphyrins / Q000737:chemistry; D014303:Trinitrotoluene / Q000737:chemistry*
chemical_list: D006454:Hemoglobins; D011524:Protoporphyrins; D014303:Trinitrotoluene; D006418:Heme; C028025:protoporphyrin IX; D007501:Iron; D009251:NADPH-Ferrihemoprotein Reductase