What is the function of beta-lactamase?

• A. Breaks down the beta-lactam ring
• B. Inhibits DNA replication
• C. Kills bacteria directly
• D. Neutralizes penicillin

Answer: (A)

Beta-lactamase is an enzyme produced by some bacteria that hydrolyzes the beta-lactam ring of beta-lactam antibiotics. That ring is essential for these drugs to bind the penicillin-binding proteins and block bacterial cell-wall synthesis. When the enzyme cleaves the ring, the antibiotic is inactivated and can no longer inhibit cell-wall formation, allowing the bacteria to continue growing. This is a key mechanism of antibiotic resistance.

The other ideas don’t fit because beta-lactamase isn’t a compound that inhibits DNA replication, nor does it kill bacteria directly. Its role isn’t to “neutralize” penicillin in a general sense, but specifically to break the beta-lactam ring so the drug can no longer work.