Mechanisms and kinetics of heme iron nitrosylation in an in vitro gastro-intestinal model
2017
de La Pomelie, Diane | Santé-Lhoutellier, Véronique | Gatellier, Philippe | Qualité des Produits Animaux (QuaPA) ; Institut National de la Recherche Agronomique (INRA) | CEPIA department of the INRA institute (France)
Fresh red meat and cured meat consumption increases the risk of gastro-intestinal cancers and it isstrongly suspected that nitrosylheme is implicated by stimulating the endogenous production of mutagenicaldehydes and N-nitroso compounds. To investigate the extent of endogenous heme iron nitrosylationan experimental in vitro model that mimics the physicochemical conditions of the gastro-intestinaltract was used in association with a mathematical model of chemical reaction kinetics. The combinedeffect of pH (from 7.2 to 3.2) and myoglobin oxidation state was evaluated in the reaction of nitrite withheme iron, and the observed rate constants of the reactions were determined. Nitrosylation was optimalunder mildly acidic conditions (pH 6.5–4.7). Up to 20% of myoglobin can be nitrosylated under gastrointestinalconditions in this pH range. The effect of various antioxidants (from meat or vegetables) onthe endogenous nitrosylation process was also tested.
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