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O 2

O 2. O 2. O 2. O 2. O 2. O 2. O 2. O 2. METABOLISM OF PYRUVATE. Its time to get aerobic. Pyruvate Structure. COO. Carboxyl group (acid). C=O. CHO. Ketone group (carbonyl). CH 3. H-C-OH. CH 2 OH. Methyl group. Glyceraldehyde. 0. 0. 3-Phosphate. - OH. O. P. CH 3.

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O 2

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  1. O2 O2 O2 O2 O2 O2 O2 O2 METABOLISM OF PYRUVATE Its time to get aerobic

  2. Pyruvate Structure COO Carboxyl group (acid) C=O CHO Ketone group (carbonyl) CH3 H-C-OH CH2OH Methyl group Glyceraldehyde 0 0 3-Phosphate -OH O P CH3 C-OH C=O C=O C O O +2 +2 +2 +2 Look for one NAD+ for each glyceraldehyde-3-PO4 oxidized to pyruvate – 2 -2 a ketoacid + 2 Net = – 2 Oxidation of Carbon –2 –2 –2 –2

  3. H3C-C-COO- O Remove as CO2 Reactions of Pyruvate (1) Decarboxylate as CO2 (2) Add CO2 (3) Reduce to alcohol (Lactate) Each is catalyzed by a specific enzyme: (1) Pyruvate decarboxylase (anaerobic -yeast) (1) Pyruvate dehydrogenase (aerobic-mitochondria) (2) Pyruvate carboxylase (mitochondria) (3) Lactate dehydrogenase (anaerobic-cytosol)

  4. H3C-C-OH H3C-C:COO- H3C-C+ H3C-C: H3C-C:H O O O O O No change in oxidation state of carbonyl C CO2 H+ CO2 NAD+ NADH H2O Oxidized carbonyl C Decarboxylation Reactions Two Types: non-oxidative and oxidative Non-oxidative Oxidative

  5. The Energy Story of Glycolysis Glucose + 2ADP + 2Pi 2 Lactate + 2ATP + 2H2O Glucose + 2ADP + 2Pi 2 Ethanol + 2CO2 +2ATP + 2H2O Glucose + 2ADP + 2Pi + 2NAD+ Overall ANAEROBIC (no O2) Yeast Overall AEROBIC 2 Pyruvate + 2ATP + 2NADH + 2H+ + 2H2O 6 ATPs

  6. C6H12O6 + 6O2 6CO2 + 6H2O COO- COO- C=O C=O CHO CH3 CH3 H-C-OH OH-C-H H-C-OH 146 100 = H-C-OH 5.2% Energy used 2,840 CH2OH C6H12O6 2 C3H4O3 Glucose 2 Pyruvate Aerobic Go’= -2,840 kJ/mol Anaerobic D-Glucose 2 Pyruvates Go’= -146 kJ/mol

  7. Glucose Glycolysis Fatty Acids Krebs Cycle 1 FADH2 3 NADH O2 H2O Anaerobic Galactose Fructose Mannose Lactate pyruvate Acetyl-Coenzyme A Aerobic Amino Acids Pyruvate dehydrogenase Complex Pyruvate dehydrogenase Thiamin pyrophosphate Dihydrolipoyl transacetylase Lipoic acid Oxidative phosphorylation Dihydrolipoyl dehydrogenase Coenzyme A FAD NAD

  8. + Carbanion : + CO2 COO CH3 C O Vitamin B-1 Pyruvate Thiamin pyrophosphate

  9. H HS-CH2-CH2-N O H CH3 O O -C-C-C-CH2-O O H -P-O-P-O HO CH3 -C-CH2-CH2-N O O CH3C O COENZYME A Acetyl-Coenzyme A Pantothenate B-vitamin Acetyl Group Adenosine-3’- phosphate Thioester bond Textbook p369

  10. Long hydrocarbon chain CH2 CH2 COO CH2 CH2 CH CH2 CH2 CH2 CH2 COO Dihydrolipoate CH CH2 CH2 CH2 CH2 HS SH 6,8 Dithiooctonoate (Reduced, gained 2 electrons) S S (Oxidized, lost 2 electrons) Disulfide bond

  11. .. CH3-C S S CH3-C S O H S H OH C-CH3 O NAD+ TPP FAD E1 E2 E3 NADH Pyruvate Dehydrogenase Complex Acetyl-CoA Textbook p471-475 HS-CoA .. .. H2 .. .. Pyruvate Dehydrogenase Dihydrolipoyl dehydrogenase Dihydrolipoyl Transacetylase

  12. Leavens bread Makes wine sparkle : : CH3-C-COO CH3-C CH3-C O CO2 O O NADH NAD+ CH3-C-H O Levels people Makes AA sparkle What about Yeast Rule: Yeast do not synthesize lactate. Instead they make acetaldehyde to regenerate NAD+ from NADH. Rule: Acetaldehyde comes from pyruvate via a non-oxidative decarboxylation. Pyruvate decarboxylase H pyruvate acetaldehyde CH3CH2OH ethanol Alcohol dehydrogenase

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