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Metabolic Biochemistry Lecture 9 August 19, 2005 Oxidative phosphorylation Other Pathways of Carbohydrate Metabolism Photosynthesis. Import of NADH into mitochondria. Example of a shuttle for oxidizing NADH from the cytosol. LNC 19-27. LNC 19-26. Getting ATP and ADP
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Metabolic Biochemistry Lecture 9 August 19, 2005 Oxidative phosphorylation Other Pathways of Carbohydrate Metabolism Photosynthesis
Import of NADH into mitochondria
Example of a shuttle for oxidizing NADH from the cytosol LNC 19-27
Getting ATP and ADP in and out of mitochondria
Biological work LNC 19-25
for NADH: P/O ratio ~ 2.5 for succinate: P/O ratio ~ 1.5
SUBSTRATE LEVEL PHOSPHORYLATION GAP + Pi + NAD+ NADH + 1,3 bisphosphoglycerate 1,3 bisphosphoglycerate + ADP ATP + 3 phosphoglycerate 1 ATP produced per NAD+ reduced per GAP used up per 3-PG produced There is a precise stoichiometry
OXIDATIVE PHOSPHORYLATION NADH + 1/2 O2 + H+ NAD+ + H2O ~ 3 ADP + ~ 3 Pi ~ 3ATP <3 ATP produced per NADH oxidized per H2O produced per 1/2 O2 consumed (P/O ratio ~ 2.5) There is no precise stoichiometry, because protons can find other paths to return to the matrix
When succinate is the substrate, the P/O ratio is ~1.5, because only two pumps are used (only 6 protons are pumped per succinate)
Mitochondria contain DNA (~16.5 kb) mtDNA encodes 2 rRNAs 22 tRNAs 13 proteins (in animals) mtDNA can have mutations causing mitochondrial diseases
GLUCONEOGENESIS LNC Chapter 14, Section 14.4 PENTOSE PHOSPHATE SHUNT LNC Chapter 14, Section 14.5
phosphatase third bypass phosphatase second bypass fructose-1,6 bisphosphate Phosphoenolpyruvate PEP first bypass pyruvate LNC Fig. 14-16
BIOTIN is a co-factor utilized for CARBOXYLATION REACTIONS THIAMINE PYROPHOSPHATE (TPP) is a co-factor utilized for DECARBOXYLATION REACTIONS LNC Fig. 14-18
first bypass in liver in muscle LNC Fig. 14-19
Chapter 15, Section 15.3 (pp.575) Coordinated Regulation of Glycolysis and Gluconeogenesis emphasis on regulation of phosphofructokinase-1 and fructose 1,6 bisphosphatase
Phosphofructokinase-1 4 identical subunits (two shown) 1 active site per subunit 1 site for allosteric regulator (ADP/ATP) LNC Fig. 15.18
Phosphofructokinase-1 PFK-1 Fructose bis-phosphatase FBPase LNC Fig. 15-22
THE PENTOSE PHOSPHATE PATHWAY Section 14.5 two significant products: ribose-phosphate NADPH
End of Lecture 9 August 19, 2005