W.X.B.6/28/20151 Production of Metabolic Energy Mitochondrial DiseasesMitochondrial Diseases Oxidation Reduction ReactionsOxidation Reduction Reactions Electron TransportElectron Transport Oxidative PhosphorylationOxidative Phosphorylation

W.X.B.6/28/20152 Mitochondrial Diseases Rare genetic diseases with maternal inheritance patterns Etiology is inability to produce ATP Diseases vary in severity with a broad range of clinical symptoms. Tissues most prominently affected are those that require the most energy: – –brain – –heart – –liver – – skeletal muscle Presently no cures, but understanding of these disease has progressed to the point where we can manage the pathologies associated with these diseases There are physicians who specialize in treating mitochondria based diseases. Mitochondrial DNA (mtDNA) codes for 13 mitochondrial proteins,Mitochondrial DNA (mtDNA) codes for 13 mitochondrial proteins, most mtDNA proteins are functionally involved in aerobic mitochondrial ATP production. most mtDNA proteins are functionally involved in aerobic mitochondrial ATP production. mtDNA is easily mutated and poorly repaired causing rapid accumulation of mutationsmtDNA is easily mutated and poorly repaired causing rapid accumulation of mutations Because mitochondria are essential to aerobic production of ATP mutations in mtDNA can be catastrophic to a cell.Because mitochondria are essential to aerobic production of ATP mutations in mtDNA can be catastrophic to a cell. High oxygen consuming tissues do so because of their large numbers of mitochondriaHigh oxygen consuming tissues do so because of their large numbers of mitochondria Mitochondria produce high levels of ATP needed to support their physiological function. The most prominent of the oxygen using tissues are brain, heart liver kidney and skeletal muscle.Mitochondria produce high levels of ATP needed to support their physiological function. The most prominent of the oxygen using tissues are brain, heart liver kidney and skeletal muscle.

W.X.B.6/28/20153 Selected Mitochondrial Diseases Mytochondrial MyopathiesMytochondrial Myopathies –Postviral Fatigue Syndrome –MERRF- Myoclonic epilepsy with ragged red fibers Neurodegenerative DiseasesNeurodegenerative Diseases –Glutamate Toxicity: –Leber Hereditary Optic Neuropathy (LHON) –Parkinsons Syndrome

W.X.B.6/28/20154 Hypothyroid Function and Mitochondrial Insufficiency

W.X.B.6/28/20155 Humans use less oxygen as they age Basal metabolic oxygen consumption declines with age.Basal metabolic oxygen consumption declines with age. Basal metabolism has 2 components:Basal metabolism has 2 components: –1. ATP using reactions. –2 Mitochondrial ATP generating reactions.

W.X.B.6/28/20156 Lactic Acidosis in Mitochondrial Insufficiency Inhibited e- transport causes high mito NADH and an lack of mito ATP.Inhibited e- transport causes high mito NADH and an lack of mito ATP. High mito NADH inhibits shuttle activity, but low ATP stimulates glycolysis.High mito NADH inhibits shuttle activity, but low ATP stimulates glycolysis. Result is production of glycolytic ATP and high cytosolic NADH.Result is production of glycolytic ATP and high cytosolic NADH. Continuation of glycolysis with ATP and NADH production leads to conversion of pyruvate to lactate and ultimately lactic acidosisContinuation of glycolysis with ATP and NADH production leads to conversion of pyruvate to lactate and ultimately lactic acidosis

W.X.B.6/28/20157 Development of Metabolic Energy ATP Synthase Electrons from donors like Succinat or NADH e.g. Succinate Fumarate + 2e- + 2H+     

W.X.B.6/28/20158 Electron Transport and Oxidative Phosphorylation: Processes of Inner Mitochondrial Membranes Inside the inner membrane is the "mitochondrial matrix". This appears moderately dense and one may find strands of DNA, ribosomes, or small granules in the matrix. The mitochondria are able to code for part of their proteins with these molecular tools. The following cartoon shows the diagram of the mitochondrial membranes and the enclosed compartments. In the right hand view, the membrane of the crista is shown with "lollipop-like" figures on their inner surface. These are elementary particles that generate ATP with its high energy bonds. We cannot see them in routine electron micrographs (see above figure). Their structure and significance will be discussed below.Inside the inner membrane is the "mitochondrial matrix". This appears moderately dense and one may find strands of DNA, ribosomes, or small granules in the matrix. The mitochondria are able to code for part of their proteins with these molecular tools. The following cartoon shows the diagram of the mitochondrial membranes and the enclosed compartments. In the right hand view, the membrane of the crista is shown with "lollipop-like" figures on their inner surface. These are elementary particles that generate ATP with its high energy bonds. We cannot see them in routine electron micrographs (see above figure). Their structure and significance will be discussed below. Internal membrane DNA Mitochondrial Ribosone F1 ATPase External membrane Matrix Space Matrix External Membrane granule

W.X.B.6/28/20159 Mitochondria: Structural Characteristics Mitochondria are the cells' power sources. They are distinct organelles with two membranes. Usually they are rod-shaped, however they can be round. The outer membrane limits the organelle. The inner membrane is thrown into folds or shelves that project inward. These are called "cristae mitochondriales". from Fawcett, A Textbook of Histology, Chapman and Hall, 12th edition, 1994.Mitochondria are the cells' power sources. They are distinct organelles with two membranes. Usually they are rod-shaped, however they can be round. The outer membrane limits the organelle. The inner membrane is thrown into folds or shelves that project inward. These are called "cristae mitochondriales". from Fawcett, A Textbook of Histology, Chapman and Hall, 12th edition, 1994.

W.X.B.6/28/ Oxidation Reduction Half Cells

W.X.B.6/28/ The Standard H 2 1/2Cell is a Reference Standard

W.X.B.6/28/ Free Energy of NADH Oxidation Conventions:Conventions: –electric potential is in volts –n = # of electrons –F = Faraday 23 kcal/volt/mol –algebraic differences are: (e- acceptor) - (e- donor)(e- acceptor) - (e- donor) CalculationsCalculations –Standard Free Energy (  G o ’) is about kcal/mol. –Std. Free Energy of ATP hydrolysis is about -7.3 kcal/mol –3 ATPs are made per NADH oxidized –Efficiency of energy conversion is about 42%! –Actual available Free Energy depends on molar concentrations of reactants and products.

W.X.B.6/28/ The Mitochondrial Electron Transfer Complexes NADH CoQ Oxidoreductase CoQH2-Cytochrome c Oxidoreductase Cytochrome c Oxidase Succinate-CoQ Oxidoreductase

W.X.B.6/28/ NAD(P)/NAD(P)H

W.X.B.6/28/ Functional Redox Forms of Flavin Nucleotides

W.X.B.6/28/ Functional forms of Coenzyme Q

W.X.B.6/28/ Nonheme Iron or Iron Sulfur Centers

W.X.B.6/28/ Simplified view of Electron Transport through Complex I

W.X.B.6/28/ Iron-Protoporphyrins (Heme) Found in Mammalian Cells

W.X.B.6/28/ Electron Transport Through Complex III

W.X.B.6/28/ Heme binding in the globin pocket of cytochrome c

W.X.B.6/28/ Complex IV (cyt. a+a3 or cyt. oxidase)

W.X.B.6/28/ Free Energy Changes in Electron Transport UQ

W.X.B.6/28/201524

W.X.B.6/28/ Malate Aspartate Shuttle P:2e - = 2.5

W.X.B.6/28/ Glycerol Phosphate Shuttle, P:2e - = 1.5