Studies on the reaction of trans-2-heptenal with peanut proteins.

Journal of agricultural and food chemistry (2014-07-30)
Martin Globisch, Marco Schindler, Jana Kreßler, Thomas Henle
ABSTRACT

Hexanal, 2-heptenal, and nonanal were identified as relevant reaction products formed in the course of the lipid peroxidation of heated peanut oil. For the identification of potential amino acid side chain adducts, kinetic studies between N(α)-benzoylglycyl-l-lysine as a model for protein-bound lysine and trans-2-heptenal were performed, showing a strong decrease of the lysine-derivative whereupon the loss of trans-2-heptenal was moderate. Following acid hydrolysis of the incubation mixture of N(α)-acetyl-l-lysine and trans-2-heptenal, two UV-active major lipation products were observed, isolated and identified as isomeric pyridinium-derivatives, namely (Z)- and (E)-1-(5-amino-5-carboxypentyl)-4-butyl-3-(pent-1-en-1-yl)pyridin-1-ium (cis- and trans-BPP-lysine). After heating of a native peanut protein extract with trans-2-heptenal, both derivatives were quantitated by LC-ESI-MS/MS after acid hydrolysis and the modification of lysine was measured by amino acid analysis. At low, "food-relevant", concentrations of trans-2-heptenal, up to 80% of the lysine modification could be explained by the formation of cis- and trans-BPP-lysine, showing that these two lipation derivatives represent good markers for a protein modification by the lipid peroxidation product trans-2-heptenal.

MATERIALS
Product Number
Brand
Product Description

Sigma-Aldrich
Methanol, Absolute - Acetone free
Sigma-Aldrich
Methanol, ACS reagent, ≥99.8%
Leucine, European Pharmacopoeia (EP) Reference Standard
Sigma-Aldrich
Methanol, suitable for HPLC, ≥99.9%
Sigma-Aldrich
Methanol, suitable for HPLC, gradient grade, ≥99.9%
Sigma-Aldrich
Methanol, HPLC Plus, ≥99.9%
Sigma-Aldrich
Methanol, ACS reagent, ≥99.8%
Sigma-Aldrich
Zirconyl chloride octahydrate, reagent grade, 98%
Sigma-Aldrich
Methanol, puriss., meets analytical specification of Ph Eur, ≥99.7% (GC)
Sigma-Aldrich
Methanol, puriss. p.a., ACS reagent, reag. ISO, reag. Ph. Eur., ≥99.8% (GC)
Sigma-Aldrich
Methanol, BioReagent, ≥99.93%
Sigma-Aldrich
Methanol, ACS spectrophotometric grade, ≥99.9%
Sigma-Aldrich
Methanol, suitable for HPLC, gradient grade, suitable as ACS-grade LC reagent, ≥99.9%
Supelco
Methanol, Pharmaceutical Secondary Standard; Certified Reference Material
Supelco
Heptaldehyde, analytical standard
Sigma-Aldrich
Methanol, Laboratory Reagent, ≥99.6%
Sigma-Aldrich
Methanol, ACS reagent, ≥99.8%
Sigma-Aldrich
Heptanal, ≥95%, FCC, FG
Sigma-Aldrich
Methanol-d4, ≥99.8 atom % D
Sigma-Aldrich
Octanal, ≥95%, FCC, FG
Sigma-Aldrich
Octanal, natural, ≥95%, FCC, FG
Sigma-Aldrich
Methanol-d4, "100%", 99.96 atom % D
Sigma-Aldrich
Methanol-d4, ≥99.8 atom % D
Supelco
1,3-Diethylbenzene, ≥98.0% (GC)
Supelco
Methanol, analytical standard
Supelco
Methanol-d4, NMR reference standard, 99.8 atom % D, NMR tube size 5 mm × 8 in.
Supelco
Methanol-d4, NMR reference standard, 99.8 atom % D, NMR tube size 3 mm × 8 in.
Supelco
Octanal, analytical standard
Sigma-Aldrich
Methanol, HPLC Plus, ≥99.9%, poly-coated bottles
Sigma-Aldrich
Methanol-d4, ≥99.8 atom % D, contains 1 % (v/v) TMS