Class C beta-lactamase enzyme

Class C beta-lactamases are enzymes produced by many Gram-negative bacteria that confer resistance to a broad range of beta-lactam antibiotics, especially cephalosporins. These enzymes hydrolyze the characteristic four-membered β‑lactam ring found in these drugs through a serine-dependent mechanism at their active site. The structure typically features two domains with conserved motifs critical for catalysis—most notably involving residues such as Ser64, Lys67, Tyr150 according to standard numbering schemes—and an omega loop important for substrate binding and specificity. Genes encoding these enzymes can be located on chromosomes or mobile genetic elements like plasmids, facilitating their spread among bacterial populations. Over 8,000 variants have been described with significant sequence diversity but conserved catalytic function. Their activity is a major driver of antimicrobial resistance globally and presents significant challenges for infection treatment due to limited efficacy of many traditional inhibitors against this enzyme class[1][2][3][4].

Other names

Class C β-lactamaseCephalosporinaseAmpC beta-lactamase (for some family members)Serine beta-lactamase (Class C type)

Hydrolyzes the four-membered β-lactam ring of antibiotics via a serine-based nucleophilic attack at the active site; this deactivates the antibiotic and confers resistance to bacteria producing these enzymes[1][2][3].