Adducts to N-terminal valines in hemoglobin from butadiene metabolites

Chem Biol Interact. 1996 Sep 6;101(3):193-205. doi: 10.1016/0009-2797(96)03724-6.

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.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Alkylation
  • Butadienes / metabolism
  • Cross-Linking Reagents
  • Epoxy Compounds / chemistry*
  • Epoxy Compounds / metabolism
  • Gas Chromatography-Mass Spectrometry
  • Hemoglobins / chemistry
  • Hemoglobins / metabolism*
  • Hydrolysis
  • Isomerism
  • Magnetic Resonance Spectroscopy
  • Mutagens / chemistry*
  • Mutagens / metabolism
  • Pyrrolidines / chemistry
  • Pyrrolidines / metabolism
  • Valine / analogs & derivatives
  • Valine / analysis
  • Valine / chemistry
  • Valine / metabolism*

Substances

  • Butadienes
  • Cross-Linking Reagents
  • Epoxy Compounds
  • Hemoglobins
  • Mutagens
  • N,N-(2,3-dihydroxybuta-1,4-diyl)valine
  • N-(2,3,4-trihydroxybutyl)valine
  • Pyrrolidines
  • diepoxybutane
  • Valine
  • pyrrolidine