title: Reverse electron transport effects on NADH formation and metmyoglobin reduction.
abstract: The objective was to determine if NADH generated via reverse electron flow in beef mitochondria can be used for electron transport-mediated reduction and metmyoglobin reductase pathways. Beef mitochondria were isolated from bovine hearts (n=5) and reacted with combinations of succinate, NAD, and mitochondrial inhibitors to measure oxygen consumption and NADH formation. Mitochondria and metmyoglobin were reacted with succinate, NAD, and mitochondrial inhibitors to measure electron transport-mediated metmyoglobin reduction and metmyoglobin reductase activity. Addition of succinate and NAD increased oxygen consumption, NADH formation, electron transport-mediated metmyoglobin reduction, and reductase activity (p<0.05). Addition of antimycin A prevented electron flow beyond complex III, therefore, decreasing oxygen consumption and electron transport-mediated metmyoglobin reduction. Addition of rotenone prevented reverse electron flow, increased oxygen consumption, increased electron transport-mediated metmyoglobin reduction, and decreased NADH formation. Succinate and NAD can generate NADH in bovine tissue postmortem via reverse electron flow and this NADH can be used by both electron transport-mediated and metmyoglobin reductase pathways.
authors.affiliation: Department of Animal Science, University of Connecticut, Storrs, CT 06269, USA.
authors.forename: K M
authors.initials: KM
authors.lastname: Belskie
authors.affiliation: Department of Animal Science, University of Connecticut, Storrs, CT 06269, USA.
authors.forename: C B
authors.initials: CB
authors.lastname: Van Buiten
authors.affiliation: Department of Animal Science, Oklahoma State University, Stillwater, OK 74078, USA.
authors.forename: R
authors.initials: R
authors.lastname: Ramanathan
authors.affiliation: Department of Animal Science, University of Connecticut, Storrs, CT 06269, USA. Electronic address: richard.mancini@uconn.edu.
authors.forename: R A
authors.initials: RA
authors.lastname: Mancini
mesh_terms: D000003:Abattoirs; D000818:Animals; D000968:Antimycin A / Q000494:pharmacology; D002417:Cattle; D004044:Dietary Proteins / Q000737:chemistry / Q000378:metabolism; D004579:Electron Transport / Q000187:drug effects; D045222:Electron Transport Chain Complex Proteins / Q000819:agonists / Q000037:antagonists & inhibitors / Q000378:metabolism*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D008786:Metmyoglobin / Q000737:chemistry / Q000378:metabolism*; D008929:Mitochondria, Heart / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism*; D008954:Models, Biological; D009243:NAD / Q000378:metabolism*; D009247:NADH, NADPH Oxidoreductases / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000378:metabolism; D010084:Oxidation-Reduction; D010085:Oxidative Phosphorylation / Q000187:drug effects; D010860:Pigments, Biological / Q000737:chemistry / Q000378:metabolism*; D012402:Rotenone / Q000494:pharmacology; D019802:Succinic Acid / Q000378:metabolism*; D014475:Uncoupling Agents / Q000494:pharmacology
chemical_list: D004044:Dietary Proteins; D045222:Electron Transport Chain Complex Proteins; D004791:Enzyme Inhibitors; D010860:Pigments, Biological; D014475:Uncoupling Agents; D012402:Rotenone; D009243:NAD; D008786:Metmyoglobin; D000968:Antimycin A; D019802:Succinic Acid; D009247:NADH, NADPH Oxidoreductases; C021794:metmyoglobin reductase
keywords: Meat color; Metmyoglobin reduction; Mitochondria; Myoglobin; Oxygen consumption