Competitive kinetics as a tool to determine rate constants for reduction of ferrylmyoglobin by food components
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Competitive kinetics as a tool to determine rate constants for reduction of ferrylmyoglobin by food components. / Jongberg, Sisse; Lund, Marianne Nissen; Pattison, David I.; Skibsted, Leif Horsfelt; Davies, Michael Jonathan.
In: Food Chemistry, Vol. 199, 2016, p. 36-41.Research output: Contribution to journal › Journal article › Research › peer-review
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TY - JOUR
T1 - Competitive kinetics as a tool to determine rate constants for reduction of ferrylmyoglobin by food components
AU - Jongberg, Sisse
AU - Lund, Marianne Nissen
AU - Pattison, David I.
AU - Skibsted, Leif Horsfelt
AU - Davies, Michael Jonathan
PY - 2016
Y1 - 2016
N2 - Competitive kinetics were applied as a tool to determine apparent rate constants for the reduction of hypervalent haem pigment ferrylmyoglobin (MbFe(IV)=O) by proteins and phenols in aqueous solution of pH 7.4 and I = 1.0 at 25 °C. Reduction of MbFe(IV)=O by a myofibrillar protein isolate (MPI) from pork resulted in kMPI = 2.2 ± 0.1 × 104 M-1 s-1. Blocking of the protein thiol groups on the MPI by N-ethylmaleimide (NEM) markedly reduced this rate constant to kMPI-NEM = 1.3 ± 0.4 × 103 M-1 s-1 consistent with a key role for the Cys residues on MPI as targets for haem protein-mediated oxidation. This approach allows determination of apparent rate constants for the oxidation of proteins by haem proteins of relevance to food oxidation and should be applicable to other systems. A similar approach has provided approximate apparent rate constants for the reduction of MbFe(IV)=O by catechin and green tea extracts, though possible confounding reactions need to be considered. These kinetic data suggest that small molar excesses of some plant extracts relative to the MPI thiol concentration should afford significant protection against MbFe(IV)=O-mediated oxidation.
AB - Competitive kinetics were applied as a tool to determine apparent rate constants for the reduction of hypervalent haem pigment ferrylmyoglobin (MbFe(IV)=O) by proteins and phenols in aqueous solution of pH 7.4 and I = 1.0 at 25 °C. Reduction of MbFe(IV)=O by a myofibrillar protein isolate (MPI) from pork resulted in kMPI = 2.2 ± 0.1 × 104 M-1 s-1. Blocking of the protein thiol groups on the MPI by N-ethylmaleimide (NEM) markedly reduced this rate constant to kMPI-NEM = 1.3 ± 0.4 × 103 M-1 s-1 consistent with a key role for the Cys residues on MPI as targets for haem protein-mediated oxidation. This approach allows determination of apparent rate constants for the oxidation of proteins by haem proteins of relevance to food oxidation and should be applicable to other systems. A similar approach has provided approximate apparent rate constants for the reduction of MbFe(IV)=O by catechin and green tea extracts, though possible confounding reactions need to be considered. These kinetic data suggest that small molar excesses of some plant extracts relative to the MPI thiol concentration should afford significant protection against MbFe(IV)=O-mediated oxidation.
KW - ABTS
KW - Competitive kinetics
KW - Ferrylmyoglobin
KW - Myofibrillar proteins
KW - Phenols
KW - Plant extracts
U2 - 10.1016/j.foodchem.2015.11.120
DO - 10.1016/j.foodchem.2015.11.120
M3 - Journal article
C2 - 26775941
AN - SCOPUS:84949035774
VL - 199
SP - 36
EP - 41
JO - Food Chemistry
JF - Food Chemistry
SN - 0308-8146
ER -
ID: 152247662