[Biochem Lec] Citric Acid Cycle

Citric Acid Cycle

Cyclic metabolic pathway that begins with the addition of Acetyl CoA to a Four-Carbon substrate

• Citric Acid Cycle

• Tricarboxylic Acid Cycle

Citric Acid Cycle is also known as?

ETC

CAC produces high-energy compounds for ATP synthesis during?

Acetyl CoA (2 C) will react to Oxaloacetate (4 C)

Overview of Step 1 in Citric Acid Cycle?

Isomerization

Overview of Step 2 in CAC?

Removal of Carbon atoms

Overview of Step 3 and 4 in CAC

Produce a side product GTP equivalent to ATP

Overview of step 5 in CAC

Oxidizing agent (NAD)

Step 3 and 4 requires what to be oxidized?

Oxidizes with FAD

Overview of Step 6 in CAC

Oxidizes with NAD yielding NADH and H

Overview of step 8 in CAC

3, 4, 6, 8

Which steps produces reducing equivalents

Citrate

In step 1 Acetyl CoA reacts with Oxaloacetate to form a 6 carbon called?

Citrate Synthase

What is the enzyme the catalyzes the reaction between Acetyl CoA and Oxaloacetate?

Tertiary Alcohol

What type of structure of alcohol is citrate in Step 1?

Isomerizes citrate into isocitrate catalyzed by aconitase

What happens in Step 2 of CAC in detail?

Aconitase

What enzyme catalyzes the isomerization of Citrate to Isocitrate in step 2 of CAC

Secondary Alcohol

When citrate is isomerized? From tertiary alcohol to?

• Isocitrate loses CO2 through decarboxylation reaction catalyzed by isocitrate dehydrogenase

• Secondary alcohol of isocitrate is oxidized by NAD forming the ketone a-ketoglutarate and NADH

What happens in Step 3 of CAC in detail?

CO2 is released by oxidation of a-ketoglutarate by NAD in the presence of Coenzyme A to form Succinyl CoA and NADH

What happens in Step 4 of CAC in detail

• Coenzyme A

In step 4 of CAC, CO2 is released by oxidation of a-ketoglutarate by NAD in the presence of _______ to form Succinyl CoA and NADH

a-ketoglutarate dehydrogenase

Step 4 is catalyzed by what enzyme?

The thioester bond of succinyl CoA is being hydrolyzed to form succinate catalyzed by succinate thiokinase, releasing energy that converts GDP into GTP

What happens in Step 5 of CAC in detail

Succinate is converted to fumarate with FAD and succinate dehydrogenase

What happens in step 6 of CAC in detail?

Fumarate is being into Malate by enzyme called Fumarase

What happens in Step 7 in detail?

Malate will be oxidized by NAD to form ketone portion of oxaloacetate and NADH catalyzed by Malate dehydrogenase

What happens in Step 8 in detail

• Acetyl CoA

• 2 Water

• 3 NAD

• FAD

• GDP

• Phosphoric Acid

Raw materials used in CAC?

• 2 CO2

• Oxaloacetate

• 3 NADH

• FADH2

• 3H

• GTP

Products in CAC

Produce reducing equivalents/reduced coenzyme

Main function of CAC is?

Mitochondria (specifically in Mitochondrial Matrix)

Where does CAC happen in terms of located organelle

Inner Mitochondrial Membrane

Where does ETC and Oxidative Phosphorylation?