Table 4.

Amino acid differences between CTX-M-4 β-lactamase and the related cefotaxime-hydrolyzing enzymes Toho-1 and CTX-M-2a

β-LactamaseAmino acid residue at position:
3948619899125171225230274
CTX-M-4SerGlnValArgAlaGlySerMetGlySer
CTX-M-2SerLeuArgLysLysAlaThrLeuValSer
Toho-1ArgLeuArgLysLysAlaThrLeuValArg
  • a Only the differences in the mature peptides are indicated. The amino acid residues were numbered according to Ambler’s system (1).