clavulanic acid

Clavulanic acid has a β-lactam ring but no antibacterial activity of its own. It inhibits a wide variety of β-lactamases (class II to class V, but not class I cephalosporinase) produced by both gram-positive and gram-negative bacteria. It is a 'progressive' or 'suicide' inhibitor, binding reversibly initially and then covalently to β-lactamase, leading to its inactivation. It permeates the outer layers of the cell wall of gram-negative bacteria and inhibits the periplasmically located β-lactamase.