3500Ch18 - Summary of the citric acid cycle For each acetyl...

Info iconThis preview shows pages 1–12. Sign up to view the full content.

View Full Document Right Arrow Icon
Summary of the citric acid cycle For each acetyl CoA which enters the cycle: (1) Two molecules of CO2 are released (2) Coenzymes NAD+ and Q are reduced (3) One GDP (or ADP) is phosphorylated (4) The initial acceptor molecule (oxaloacetate) is reformed
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Stage 1 Stage 2
Background image of page 2
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Reaction 1. Citrate Synthase Only cycle reaction with C-C bond formation Feeder reaction, is not coupled to ATP formation , instead the reaction ensures flux into the TCA Thought to be metabolically irreversible , oxaloacetate is at too low of a concentration to accurately measure in the matrix Aldol condensation reaction, then hydrolysis to form citrate
Background image of page 4
Critical step in the pathway! Mechanism involves sequential ordered reactions – reduces undesirable side reactions Namely hydrolysis of acetyl-CoA Oxaloacetate binds first induces a major conformational change this change creates an acetyl-CoA binding site
Background image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Background image of page 6
Reaction 2: Aconitase An isomerase based on product formed. Mechanistically, like a lyase. Dehydration Hydration
Background image of page 7

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Aconitase – an iron sulfur protein (non- heme)
Background image of page 8
Suicide Inhibitor of Aconitase
Background image of page 9

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Reaction 3. Isocitrate The first of four oxidation-reduction reactions of the cycle, oxidative decarboxylation H- from C2 of isocitrate is transferred to NAD+ forming NADH Regulated step Oxalosuccinate is an unstable β-keto acid
Background image of page 10
Reaction 4. The α -Ketoglutarate Similar to pyruvate dehydrogenase complex Same coenzymes, identical mechanisms
Background image of page 11

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 12
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 02/03/2011 for the course CHEM 3500 taught by Professor Staff during the Spring '08 term at Kennesaw.

Page1 / 38

3500Ch18 - Summary of the citric acid cycle For each acetyl...

This preview shows document pages 1 - 12. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online