INBDE (Integrated National Board Dental Examination) Practice Exam

What is the function of lactoperoxidase?

1. Inactivates enzymes

2. Destroys cell walls

3. Inactivates iron

4. Activates iron

The correct answer is: Inactivates enzymes

Lactoperoxidase is an enzyme naturally found in saliva and milk that plays a role in protecting the oral cavity against pathogens. One of its primary functions is to inactivate enzymes produced by bacteria, which helps to modulate the growth of bacteria in the oral environment. By inhibiting bacterial enzymes, lactoperoxidase can disrupt the metabolic processes of bacteria, ultimately leading to their reduced viability. This mechanism contributes to the overall defense system present in saliva to maintain oral health. Regarding the other options: - Option B, "Destroys cell walls," is not the function of lactoperoxidase. While some enzymes or compounds may target bacterial cell walls, lactoperoxidase primarily acts on bacterial enzymes. - Option C, "Inactivates iron," is not the correct function of lactoperoxidase. Lactoferrin is an example of an enzyme that binds and sequesters iron, unlike lactoperoxidase. - Option D, "Activates iron," is also not the correct function of lactoperoxidase. This enzyme primarily serves a defensive role against bacteria through enzyme inactivation rather than activating iron ions.