1 / 20

Pyruvate Oxidation: Pyruvate Dehydrogenase and the TCA Cycle

Pyruvate Oxidation: Pyruvate Dehydrogenase and the TCA Cycle. Aerobic “respiration” in mitochondria: important for ATP synthesis and a source of intermediates for other biochemical pathways pyruvate (C 3 H 3 O 3 ) + 4 NAD + + FAD + GDP + Pi + 2H 2 O

badru
Download Presentation

Pyruvate Oxidation: Pyruvate Dehydrogenase and the TCA Cycle

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Pyruvate Oxidation: Pyruvate Dehydrogenase and the TCA Cycle

  2. Aerobic “respiration” in mitochondria: important for ATP synthesis • and a source of intermediates for other biochemical pathways • pyruvate (C3H3O3) + 4 NAD+ + FAD + GDP + Pi + 2H2O • 3 CO2 + 4 NADH + 3 H+ + FADH2 + GTP • First step: pyruvate dehydrogenase

  3. Pyruvate dehydrogenase function

  4. Acetyl-CoA is oxidized in the citric acid (Kreb’s, TCA) cycle

  5. TCA Cycle

  6. Recap TCA cycle: • acetyl-CoA(C2H3O-CoA) + 3 NAD+ + FAD + GDP + Pi + 2H2O • CoA-SH + 2 CO2 + 3 NADH + 3 H+ + FADH2 + GTP • Include pyruvate oxidation: • pyruvic acid(C3H4O3) + 4 NAD+ + FAD + GDP + Pi + 2H2O • 3 CO2 + 4 NADH + 4 H+ + FADH2 + GTP • Complete oxidation of the pyruvate carbons • Reduction of 4 NAD+ and one FAD • Phosphorylation of one GDP

  7. The TCA cycle is a source of biosynthetic precursors But what happens when intermediates are removed from the cycle?

  8. Without intermediates, the cycle stops! “Anaplerotic” reactions replenish the intermediates. Pyruvate + CO2 + ATP + H2O OAA + ADP + Pi + 2 H+

  9. A modification of the TCA cycle (glyoxylate cycle) lets plants and bacteria make carbohydrates from fats. to glucose isocitric lyase malate synthase

  10. Summary • The TCA cycle gives complete oxidation of the pyruvate carbons. • And reduction of 4 NAD+ and one FAD. • And phosphorylation of one GDP. • The TCA cycle is a source of biosynthetic precursors. • Pyruvate carboxylase and the glyoxylate cycle replenish precursors • Replenishment of NAD + and FAD are also essential.

More Related