Cephalosporinases

Cephalosporinases are a class of enzymes that catalyze the hydrolysis of the beta-lactam ring of cephalosporin antibiotics, rendering them inactive. These enzymes are produced by various bacteria and fungi, and their activity can lead to the failure of cephalosporin-based therapies. Cephalosporinases are classified into three main types based on their substrate specificity and mechanism of action: cephalosporinase I, II, and III. Cephalosporinase I is the most common and is found in many Gram-negative bacteria. It is a metalloenzyme that requires zinc for its activity and is inhibited by certain metal chelators. Cephalosporinase II is found in some Gram-positive bacteria and is a serine enzyme that is inhibited by serine protease inhibitors. Cephalosporinase III is found in some fungi and is a serine enzyme that is inhibited by serine protease inhibitors. The activity of cephalosporinases can be measured using various assays, including the agar diffusion assay and the turbidimetric assay. The development of cephalosporinase-resistant cephalosporins has been a major focus of antibiotic research, with the goal of creating antibiotics that are less susceptible to inactivation by these enzymes.