title: Competitive reduction of perferrylmyoglobin radicals by protein thiols and plant phenols.
abstract: Radical transfer from perferrylmyoglobin to other target species (myofibrillar proteins, MPI) and bovine serum albumin (BSA), extracts from green tea (GTE), maté (ME), and rosemary (RE), and three phenolic compounds, catechin, caffeic acid, and carnosic acid) was investigated by electron paramagnetic resonance (EPR) spectroscopy to determine the concentrations of plant extracts required to protect against protein oxidation. Blocking of MPI thiol groups by N-ethylmaleimide was found to reduce the rate of reaction of MPI with perferrylmyoglobin radicals, signifying the importance of protein thiols as radical scavengers. GTE had the highest phenolic content of the three extracts and was most effective as a radical scavenger. IC50 values indicated that the molar ratio between phenols in plant extract and MPI thiols needs to be >15 in order to obtain efficient protection against protein-to-protein radical transfer in meat. Caffeic acid was found most effective among the plant phenols.
authors.affiliation: Department of Food Science, Faculty of Science, University of Copenhagen , Rolighedsvej 30, 1958 Frederiksberg, Denmark.
authors.forename: Sisse
authors.initials: S
authors.lastname: Jongberg
authors.forename: Marianne N
authors.initials: MN
authors.lastname: Lund
authors.forename: Leif H
authors.initials: LH
authors.lastname: Skibsted
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Davies
mesh_terms: D000818:Animals; D002417:Cattle; D005609:Free Radicals / Q000737:chemistry*; D006736:Horses; D030017:Ilex / Q000737:chemistry*; D007501:Iron / Q000737:chemistry; D009124:Muscle Proteins / Q000737:chemistry*; D009211:Myoglobin / Q000737:chemistry*; D010636:Phenols / Q000737:chemistry*; D010936:Plant Extracts / Q000737:chemistry*; D012710:Serum Albumin, Bovine / Q000737:chemistry; D013438:Sulfhydryl Compounds / Q000737:chemistry*; D013552:Swine
chemical_list: D005609:Free Radicals; D009124:Muscle Proteins; D009211:Myoglobin; D010636:Phenols; D010936:Plant Extracts; D013438:Sulfhydryl Compounds; C066318:perferryl iron; D012710:Serum Albumin, Bovine; D007501:Iron
keywords: myofibrillar proteins; myoglobin; plant phenols; protein oxidation; protein radicals