Serine beta-lactamase (Class A, C, or D)

Serine beta-lactamases (classes A, C, and D) are a broad family of enzymes found in bacteria that confer resistance to β-lactam antibiotics by catalyzing the hydrolysis of the β-lactam ring using an active-site serine residue[2][5]. These enzymes are genetically diverse, structurally conserved around their catalytic mechanism, and classified according to molecular sequence and function. Their clinical importance is highlighted by their role in antibiotic resistance in major Gram-negative and some Gram-positive pathogens, leading to significant therapeutic challenges and driving the development of β-lactamase inhibitors[4][2][5][7]. Note: "Class A, C, and D serine β-lactamases" as a term is a superclass rather than a single canonical drug/protein target. Individual genes/proteins (e.g., TEM-1, OXA-1, AmpC) should be referenced for precise drug-target annotation[2][5][7]. These classes are distinct from class B β-lactamases (metallo-β-lactamases), which use a zinc ion for catalysis, not serine[2][5][6].

Other names

β-lactamase (class A, C, D)Serine β-lactamaseAmbler class A/C/D β-lactamaseAmpC (class C)OXA (class D)TEMSHVKPC

Targeted drugs can inhibit the enzyme's serine-based hydrolysis of the β-lactam ring (e.g., covalent acylation of active-site serine by inhibitors). Some drugs evade hydrolysis due to poor recognition (e.g., certain cephamycins or carbapenems).