TY - JOUR
T1 - Influence of the Oxidation States of 4-Methylcatechol and Catechin on the Oxidative Stability of β-Lactoglobulin
AU - Jongberg, Sisse
AU - Utrera, Mariana
AU - Morcuende, David
AU - Lund, Marianne N.
AU - Skibsted, Leif Horsfelt
AU - Estévez, Mario
PY - 2015/9/30
Y1 - 2015/9/30
N2 - Chemical interactions between proteins and phenols affect the overall oxidative stability of a given biological system. To investigate the effect of protein-phenol adduct formation on the oxidative stability of β-lactoglobulin (β-LG), the protein was left to react with an equimolar concentration of 4-methylcatechol (4MC), catechin (Cat), or their respective quinone forms, 4-methylbenzoquinone (4MBQ) and catechin-quinone (CatQ), and subsequently subjected to metal-catalyzed oxidation by Fe(II)/H2O2 for 20 days at 37 °C. The reaction with 4MBQ resulted in 60% thiol loss and 22% loss of amino groups, whereas the addition of 4MC resulted in 12% thiol loss. The reaction with Cat or CatQ resulted in no apparent modification of β-LG. The oxidative stability of β-LG after reaction with each of 4MC, 4MBQ, Cat, or CatQ was impaired. Especially 4MC and 4MBQ were found to be pro-oxidative toward α-aminoadipic semialdehyde and γ-glutamic semialdehyde formation as well as the generation of fluorescent Schiff base products. The changes observed were ascribed to the redirection of oxidation as a result of the blocking of thiol groups but also to the oxidative deamination pathway, accelerating the production of semialdehydes and subsequently Schiff base structures.
AB - Chemical interactions between proteins and phenols affect the overall oxidative stability of a given biological system. To investigate the effect of protein-phenol adduct formation on the oxidative stability of β-lactoglobulin (β-LG), the protein was left to react with an equimolar concentration of 4-methylcatechol (4MC), catechin (Cat), or their respective quinone forms, 4-methylbenzoquinone (4MBQ) and catechin-quinone (CatQ), and subsequently subjected to metal-catalyzed oxidation by Fe(II)/H2O2 for 20 days at 37 °C. The reaction with 4MBQ resulted in 60% thiol loss and 22% loss of amino groups, whereas the addition of 4MC resulted in 12% thiol loss. The reaction with Cat or CatQ resulted in no apparent modification of β-LG. The oxidative stability of β-LG after reaction with each of 4MC, 4MBQ, Cat, or CatQ was impaired. Especially 4MC and 4MBQ were found to be pro-oxidative toward α-aminoadipic semialdehyde and γ-glutamic semialdehyde formation as well as the generation of fluorescent Schiff base products. The changes observed were ascribed to the redirection of oxidation as a result of the blocking of thiol groups but also to the oxidative deamination pathway, accelerating the production of semialdehydes and subsequently Schiff base structures.
U2 - 10.1021/acs.jafc.5b02551
DO - 10.1021/acs.jafc.5b02551
M3 - Journal article
SN - 0021-8561
VL - 63
SP - 8501
EP - 8509
JO - Journal of Agricultural and Food Chemistry
JF - Journal of Agricultural and Food Chemistry
IS - 38
ER -