BIOLCHEM 415 1st Edition Lecture 21Outline of Last Lecture I. An overview of the electron transport chainII. Complexes I-IV and the reactions they catalyzeIII. Reactive oxygen species Outline of Current Lecture IV. ATP synthase is powered by the proton gradientV. ATP synthase is composed of two large sectionsCurrent LectureProton gradient drive ATP synthesis- ATP synthase couples NADH reaction- like a water wheel- electrons can’t be used to directly synthesize ATP- therefore the proton gradient does- an actual wheel is involved (C ring)ATP synthase- ATP made through condensation of ADP and Pi- Mg2+ complexes of ADP/ATP are the substrates- reversible reaction- converts the energy of proton gradient to ATP synthesis- has 2 large sections (F0 and F1)- F0 in membrane (C ring and A subunit)- F1 in mitochondrial matrix (3α, 3β, δ, ε, and γ)These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.- the catalytic sectionγ subunit’s effect on the β subunits- as γ subunit rotates it change the conformation of the β subunits- L (Loose) – binds to ADP and Pi weakly- T (Tight) – favors ATP which favors ATP formation- O (Open) – binds weakly, permitting dissociation, releases ATP- α subunits – bind to ATP but not a part of catalysis Rotation of C ring - hydrophilic ½ channels in A subunit allow proton conduction- drives the rotation of the C ring which drives the rotation of the γ subunit- yields ~ 3 ATP~ 26 ATP produced from ATP synthaseMalate-Aspartate shuttle - in liver and heart- used to transfer the electrons from NADH in cytoplasm to a molecule of NADH in mitochondrial matrix- other tissues use glycerol-3-phophate shuttleATP-ADP translocase- ATP and ADP are membrane impermeable- ADP from cytoplasm matrix- ATP from matrix cytoplasmThermogenesis- heat production- the uncoupling of oxidative phosphorylation from ATP synthesis- brown adipose tissue – nonshivering thermogenesis- express Uncoupling Protein 1 (UCP1)- forms channel that allows protons to pass from intermembrane space to matrix- generates large amounts of
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