Lecture24-2007 - Citric Acid Cycle 1 Lecture 24 Chapter 16-3 Citric Acid Cycle Other names Krebs cycle Tricarboxylic Acid Cycle(TCA Circular

Info iconThis preview shows pages 1–4. Sign up to view the full content.

View Full Document Right Arrow Icon
1 Citric Acid Cycle 1 Lecture 24 Chapter 16-3 Citric Acid Cycle • Other names: Krebs cycle, Tricarboxylic Acid Cycle (TCA). • Circular pathway: all intermediates are “catalytic” (no net formation or consumption). • Complete oxidation of Acetate to CO 2 . – 8 steps, 4 of which are oxidations. • Electrons will be transferred into electron transport to generate ATP through Ox. Phos. • Balanced equation: Acetyl-CoA + 3 NAD + + FAD + GDP + Pi --> 2 CO 2 + 3 NADH + FADH 2 + GTP + CoA
Background image of page 1

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

View Full DocumentRight Arrow Icon
2 Reaction 1: Citrate Synthase Acetyl-CoA + OAA + H 2 O ---> Citrate + CoA Coupled reaction: Condensation of methyl group of Acetate to carbonyl of OAA (unfavorable). Hydrolysis of thioester (favorable). Overall reaction favorable. Irreversible in cells. Ordered binding of substrates (OAA first) prevents premature hydrolysis of thioester. Citrate Synthase in absence of OAA “Open” structure Citrate Synthase in presence of OAA “Closed” structure. Acetyl-CoA binds to the closed structure. Ensures that the enzyme only binds Acetyl-CoA when OAA is available. Hexokinase works the same way. Citrate Synthase mechanism (after both substrates are bound): Enol Enzyme-bound intermediate
Background image of page 2
3 Reaction 2: Aconitase Reversible isomerization of citrate and isocitrate. Enzyme bound intermediate: cis-Aconitate Contains an Iron-Sulfur cluster for binding substrate.
Background image of page 3

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

View Full DocumentRight Arrow Icon
Image of page 4
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 04/09/2008 for the course BIOCHEMIST 361 taught by Professor Haltiwanger during the Fall '08 term at SUNY Stony Brook.

Page1 / 9

Lecture24-2007 - Citric Acid Cycle 1 Lecture 24 Chapter 16-3 Citric Acid Cycle Other names Krebs cycle Tricarboxylic Acid Cycle(TCA Circular

This preview shows document pages 1 - 4. Sign up to view the full document.

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