Chloramphenicol acetyltransferase (CAT) (CAT)

Chloramphenicol acetyltransferase (CAT) is a bacterial enzyme that provides resistance to the antibiotic chloramphenicol by catalyzing the acetylation of the drug [1, 2]. This enzyme transfers an acetyl group from acetyl-CoA to the 3-hydroxyl group of chloramphenicol, which prevents the antibiotic from binding to the bacterial 50S ribosomal subunit and inhibiting protein synthesis [2, 4]. CAT is found in various bacterial species and is often carried on plasmids or transposons, contributing significantly to the spread of multi-drug resistance [1, 3]. In molecular biology, the CAT gene is commonly used as a reporter gene to monitor gene expression and promoter activity in transfected cells [2]. While chloramphenicol use has declined in some regions due to toxicity, CAT remains a critical target for understanding and overcoming antimicrobial resistance mechanisms [4]. Efforts to develop CAT inhibitors aim to restore the efficacy of chloramphenicol against resistant bacterial strains [3]. The enzyme typically exists as a homotrimer, and its active site is located at the interface between adjacent subunits [1].

Other names

Chloramphenicol 3-O-acetyltransferaseCAT enzymeType I chloramphenicol acetyltransferaseType II chloramphenicol acetyltransferaseType III chloramphenicol acetyltransferase

CAT inactivates chloramphenicol by transferring an acetyl group from acetyl-CoA to the C3-hydroxyl group of the antibiotic, preventing it from binding to the 50S ribosome; inhibitors of CAT aim to block this acetylation to restore drug efficacy [1, 4].