Leucine Deamination and Oxidation

The video tutorial explains the catabolic pathway of leucine, highlighting its differences from valine catabolism. It details the enzymatic reactions involved, including the role of branched-chain transaminase and dehydrogenase complexes. The tutorial discusses the energy yield from leucine catabolism, emphasizing the importance of electron transferring flavoproteins. It also explores the biochemical pathways leading to products like acetyl CoA and acetoacetate. Finally, the video summarizes the process and calculates the energy yield, providing a comprehensive understanding of leucine catabolism.

What is the primary difference between leucine and valine catabolism?

• Leucine catabolism is an anabolic process, while valine catabolism is catabolic.

• Leucine catabolism occurs in the cytoplasm, while valine catabolism occurs in the mitochondria.

• Leucine catabolism produces HMG-CoA, while valine catabolism produces propionyl-CoA.

• Leucine catabolism uses different enzymes than valine catabolism.

Which enzyme is involved in the initial transamination of leucine?

• Pyruvate dehydrogenase

• Branched-chain transaminase

• Succinate dehydrogenase

• Alpha-ketoglutarate dehydrogenase

What is the role of the branched-chain alpha-ketoacid dehydrogenase complex in leucine catabolism?

• It converts leucine into glucose.

• It synthesizes fatty acids from leucine.

• It catalyzes the decarboxylation of alpha-ketoacids.

• It phosphorylates leucine.

During the FAD-dependent oxidation in leucine catabolism, what is the initial electron acceptor?

• Cytochrome C

• NAD+

• Coenzyme Q

• Electron transferring flavoprotein

What is the final product of the carboxylation reaction in leucine catabolism?

• Hydroxymethylglutaryl-CoA

• Propionyl-CoA

• 3-methylglutaconyl-CoA

• Acetyl-CoA

Which enzyme catalyzes the hydration of 3-methylglutaconyl-CoA?

• 3-methylglutaconyl-CoA hydratase

• Isovaleryl-CoA dehydrogenase

• Pyruvate carboxylase

• Acetyl-CoA carboxylase

What are the two main products formed when HMG-CoA is cleaved?

• Malonyl-CoA and citrate

• Oxaloacetate and fumarate

• Propionyl-CoA and succinate

• Acetyl-CoA and acetoacetate

How many NADH molecules are produced from the complete catabolism of leucine?

• 11

• 5

• 8

• 14

What is the net ATP yield from leucine catabolism?

• 1 ATP

• 2 ATP

• 3 ATP

• 4 ATP

Which molecule is a key intermediate in both leucine catabolism and cholesterol biosynthesis?

• Propionyl-CoA

• HMG-CoA

• Fumarate

• Acetoacetate