Catalytic Mechanism of Myeloperoxidase & Hypochlorous Acid Functions

The video tutorial explains the enzyme myeloperoxidase, its mechanism, and its role in the immune system. Myeloperoxidase, expressed by neutrophils, generates hypochlorous acid, a reactive oxidative species used to oxidize proteins of invading pathogens. The mechanism involves a heme moiety and hydrogen peroxide, leading to the formation of hypochlorous acid, which damages proteins by oxidizing cysteine residues. The video also covers the generation of hypothyroid cyanide, another reactive species, and its impact on proteins.

What is the primary function of myeloperoxidase in neutrophils?

• To transport oxygen

• To repair damaged cells

• To generate hypochlorite for pathogen destruction

• To synthesize proteins

Which molecule serves as the substrate for myeloperoxidase?

• Oxygen

• Hydrogen peroxide

• Water

• Chlorine

What is the significance of the iron oxy species in the myeloperoxidase mechanism?

• It transports electrons to the cell membrane

• It stabilizes the enzyme structure

• It facilitates the generation of reactive oxidative species

• It acts as a reducing agent

What is the role of hypochlorous acid in the biochemical context?

• It stabilizes cell membranes

• It acts as a reducing agent

• It oxidizes proteins, particularly cysteine residues

• It enhances protein synthesis

How does hypochlorous acid affect cysteine residues in proteins?

• It stabilizes their structure

• It enhances their nucleophilic properties

• It converts them into functional disulfide bridges

• It transforms them into sulfonic acid, rendering them non-functional

What is hypothyroid cyanide, and how is it generated?

• A reactive oxidative species generated by myeloperoxidase using thiocyanate

• A stable compound formed during protein synthesis

• A byproduct of cellular respiration

• A free radical generated by oxygen

What is the structural difference between hypochlorous acid and hypothyroid cyanide?

• Hypochlorous acid contains chlorine, while hypothyroid cyanide contains thiocyanate

• Hypochlorous acid is a free radical, while hypothyroid cyanide is not

• Hypochlorous acid is a reducing agent, while hypothyroid cyanide is an oxidizing agent

• Hypochlorous acid is stable, while hypothyroid cyanide is unstable