Cytochrome P450 1

The video tutorial provides an in-depth exploration of cytochrome P-450, the largest gene superfamily of enzymes in the human body. It covers the enzyme's primary functions in steroidogenesis and drug catabolism. The structure of heme B, a key component of cytochrome P-450, is discussed, highlighting its aromatic ring and chelation of iron. The tutorial explains the mechanism of oxygen activation and the electron transfer process involving NADPH and P-450 reductase, using the cholesterol side chain cleavage enzyme as an example.

What is one of the primary functions of cytochrome P-450 enzymes in the human body?

• Carbohydrate metabolism

• Steroidogenesis

• Protein synthesis

• Lipid storage

Which of the following is a component of the heme B structure?

• Phosphate groups

• Vinyl groups

• Sulfate groups

• Nitrate groups

What is the oxidation state of iron in the heme B when cytochrome P-450 begins its catalysis?

• 0

• 4+

• 3+ (ferric)

• 2+ (ferrous)

What is the role of the iron in the center of the heme B?

• To transport electrons

• To store energy

• To activate molecular oxygen

• To bind with water molecules

What is the significance of the aromatic ring in heme B?

• It makes the heme B water-soluble

• It allows for rapid degradation

• It provides structural stability

• It binds with glucose

What is the role of the cysteine residue in the structure of cytochrome P-450?

• To store electrons

• To chelate the iron

• To bind with oxygen

• To synthesize heme

How does cytochrome P-450 receive electrons during its catalytic cycle?

• From ATP hydrolysis

• From NADPH via P-450 reductase

• Directly from oxygen

• Through light absorption

Which molecule donates electrons to cytochrome P-450?

• FADH2

• ATP

• NADPH

• NADH

What is the function of adrena doxin reductase in the cholesterol side chain cleavage process?

• To oxidize cholesterol

• To transport electrons to P-450

• To bind with oxygen

• To synthesize cholesterol

In which cellular location would you find mitochondrial P-450 reductase?

• Cytoplasm

• Nucleus

• Mitochondria

• Golgi apparatus