title: Adducts to N-terminal valines in hemoglobin from butadiene metabolites.
abstract: In order to identify a hemoglobin adduct useful for monitoring of doses of butadiene metabolites, particularly the strongly genotoxic, bifunctional diepoxybutane (DEB), the reaction of DEB with valinamide, a relevant model of globin N-termini, was studied. A preliminary kinetic analysis showed that the primary reaction product of DEB with valine-N gives, as was expected, rise to a ring-closed pyrrolidine-structured compound, N,N-(2,3-dihydroxybuta-1,4-diyl)valine (PYRV), in a reaction which is fast when compared to hydrolysis of the second oxirane ring with formation of N-(2,3,4-trihydroxybutyl)valine (THBV). The ring closure is also fast when compared to the rate of formation of a cross-linked divaline product. PYRV can therefore be used as a specific marker of in vivo doses of DEB whereas THBV may be applied for the dosimetry of the metabolite (1,2-dihydroxyethyl)oxirane. The latter is formed by half-hydrolysis of DEB or oxygenation of 1,2-dihydroxy-3-butene. The N-alkyl Edman method, used for specific cleavage and gas chromatographic/mass spectrometric (GC/MS) determination of adducts to N-terminal valine in hemoglobin, could be used for measurement of THBV, as shown in alkylation experiments with blood. However, the adduct specific for DEB, PYRV, requires-due to its tertiary amine structure-other techniques. The reaction products were identified by GC/MS, PYRV by 13C and 1H NMR, and THBV because of its formation by reduction of the Schiff bases of threose and erythrose with hemoglobin.
authors.affiliation: Department of Environmental Chemistry, Stockholm University, Sweden.
authors.forename: P
authors.initials: P
authors.lastname: Rydberg
authors.forename: A L
authors.initials: AL
authors.lastname: Magnusson
authors.forename: V
authors.initials: V
authors.lastname: Zorcec
authors.forename: F
authors.initials: F
authors.lastname: Granath
authors.forename: M
authors.initials: M
authors.lastname: Törnqvist
mesh_terms: D000478:Alkylation; D002070:Butadienes / Q000378:metabolism; D003432:Cross-Linking Reagents; D004852:Epoxy Compounds / Q000737:chemistry* / Q000378:metabolism; D008401:Gas Chromatography-Mass Spectrometry; D006454:Hemoglobins / Q000737:chemistry / Q000378:metabolism*; D006868:Hydrolysis; D007536:Isomerism; D009682:Magnetic Resonance Spectroscopy; D009153:Mutagens / Q000737:chemistry* / Q000378:metabolism; D011759:Pyrrolidines / Q000737:chemistry / Q000378:metabolism; D014633:Valine / Q000031:analogs & derivatives / Q000032:analysis / Q000737:chemistry / Q000378:metabolism*
chemical_list: D002070:Butadienes; D003432:Cross-Linking Reagents; D004852:Epoxy Compounds; D006454:Hemoglobins; D009153:Mutagens; C101917:N,N-(2,3-dihydroxybuta-1,4-diyl)valine; C101918:N-(2,3,4-trihydroxybutyl)valine; D011759:Pyrrolidines; C007366:diepoxybutane; D014633:Valine; C032519:pyrrolidine