Chloramphenicol acetyltransferase (CAT) [PMID:1867721] catalyses the acetyl-CoA dependent acetylation of chloramphenicol (Cm), an antibiotic which inhibits prokaryotic peptidyltransferase activity. Acetylation of Cm by CAT inactivates the antibiotic. A histidine residue, located in the C-terminal section of the enzyme, plays a central role in its catalytic mechanism. CAT enzymes are divided into three classes: CATI, CATII, and CATIII, with the enzymes of all three classes catalysing acetyl transfer to CAM to yield 3-O-acetyl-CAM. This entry represents the type III protein, although the mechanism is likely to be similar between the three classes.
Defined by 4 residues: ARG:A-13 [auth A-18]THR:A_3-168 [auth A_3-174]HIS:A-189 [auth A-195]ASP:A-193 [auth A-199]
