Table 5.
Enzyme types and their activity against antibiotics.
| Class | Active Site | Enzyme Type | Substrates |
|---|---|---|---|
| A | Serine | Penicillinases: | |
| Broad-spectrum | Benzylpenicillin, aminopenicillins, carboxypenicillins, ureidopenicillins, narrow-spectrum Cephalosporins |
||
| Extended-spectrum (β-lactamase) |
Substrates of broad-spectrum plus oxymino-β-lactams (cefotaxime, ceftazidime, ceftriaxone) and aztreonam |
||
| Carbapenemases | Substrates of extended-spectrum plus cephamycins and carbapenems |
||
| B | Zn2+ | Carbapenemases | Substrates of extended-spectrum plus cephamycins and carbapenems |
| C | Serine | Cephalosporinases | Substrates of extended-spectrum plus cephamycins |
| D | Serine | Oxacillinases: | |
| Broad-spectrum | Aminopenicillins, ureidopenicillin, cloxacillin, methicillin, oxacillin, and some narrow-spectrum cephalosporins |
||
| Extended-spectrum (β-lactamase) |
Substrates of broad-spectrum plus oxymino-β-lactams and monobactams |
||
| Carbapenemases | Substrates of extended-spectrum plus cephamycins and carbapenems |