BIBC 102: Metabolic Biochemistry (Prof. Scheffler) TA: Edward Chen [email protected] Section: Mondays 4-5pm Center 218 OH: Wednesdays 10-11am @ CLICS Handout #5 (2/27/06) A. Mitochondria • Outer membrane – porins, permeable membranes • Inner membrane – impermeable membrane, respiratory chain, ATP, ADP transporters, ATP synthase o Inner membrane molecules: Ubiquinone (coenzyme Q) Cytochromes Iron-Sulfur (centers) • Matrix – pyruvate dehydrogenase complex, Krebs enzymes, and proteins B. Electron Transport Chain • Respiratory Chain (electron transport chain) o Prone to reduce molecules as the electrons move down the chain • Respiratory Inhibitors o Have the ability to stop the respiratory chain at certain sites. Can be used to isolate membrane proteins and study them. Inhibition in one site results in reduced electron transport chain upstream and oxidized chain downstream.BIBC 102: Metabolic Biochemistry (Prof. Scheffler) TA: Edward Chen [email protected] Section: Mondays 4-5pm Center 218 OH: Wednesdays 10-11am @ CLICS C. Synthesis of ATP • Complexes I-IV pump H+ from _______________ to create __________________ • Proton motive force – the net effect due to difference in chemical concentration and charge distribution across the inner mitochondrial membrane o ∆G = 2.3 RT ∆pH + ZF x ∆Ψ ∆pH – ∆Ψ – Z – • Tightly coupled mitochondria • Uncoupled mitochondria o Valinomycin is a K+ ionophore o Nigericin is a H + /K + antiporter o These guys are ANTIBIOTICS… you know their purpose o.OBIBC 102: Metabolic Biochemistry (Prof. Scheffler) TA: Edward Chen [email protected] Section: Mondays 4-5pm Center 218 OH: Wednesdays 10-11am @ CLICS D. ATP Synthase • F1 subunit = α3β3γδε o The 3 β subunits have one catalytic site for ATP synthesis o γ subunit is called the “cam shift” o Rotary motor – o ATP synthase can produce ATP without a proton gradient. o The role of the proton gradient is not to form ATP, but to release ATP from the synthase. • Fo subunit = a b2 c9-12 o Oligomycin: E. Thermoregulation / Thermogenesis • Uncoupling of phosphorylation to produce heat instead of ATP • DNP: • UCP: uncoupling protein (aka thermogenin) o o o o o o • In the presence of an uncoupler, the P/O ratio is reduced to zero F. Substrate Level Phosphorylation and Oxidative Phosphorylation • Substrate Level Phosphorylation o • Oxidative Phosphorylation
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