What is the mechanism of action of Penicillin VK?

Penicillin VK (phenoxymethylpenicillin) is a beta-lactam antibiotic that works by binding covalently to penicillin-binding proteins (PBPs) - bacterial enzymes called transpeptidases that catalyze the cross-linking of peptidoglycan strands in the bacterial cell wall. By inhibiting transpeptidase, penicillin prevents cell wall synthesis, causing cell wall weakening and eventual lysis (bactericidal). Beta-lactam antibiotics are most effective against actively dividing bacteria. Bacterial resistance occurs through beta-lactamase production, modified PBPs (MRSA), and reduced membrane permeability.