Table 5.
d,d-peptidase (VanXYN) and racemase (VanTN) activities in extracts from E. faecium UCN71
| Vancomycin concn (μg/ml) | Activity (nmol min−1 mg protein−1) of indicated protein or enzymea |
|||||
|---|---|---|---|---|---|---|
| Cytoplasmic fraction of d,d-dipeptidaseb |
d,d-carboxypeptidasec |
Membrane fraction of d-serine racemased |
d-alanine racemasec |
|||
| Cytoplasmic fraction | Membrane fraction | Cytoplasmic fraction | Membrane fraction | |||
| 0 | 49 ± 6 | 33 ± 2 | 9 ± 2 | 77 ± 20 | 18 ± 1 | 8 ± 2 |
| 4 | 47 ± 3 | 28 ± 1 | 10 ± 2 | 83 ± 15 | 18 ± 3 | 11 ± 2 |
| 8 | 52 ± 10 | 27 ± 2 | 10 ± 1 | 67 ± 10 | 12 ± 1 | 7 ± 1 |
a
Results are the means ± standard deviations obtained from a minimum of three independent extracts.
b
d,d-dipeptidase activity was measured in the supernatants of lysed bacteria after centrifugation at 100,000 × g.
c
d,d-carboxypeptidase and d-alanine racemase activities were measured in the supernatants and in the resuspended pellet fractions after centrifugation of lysed bacteria at 100,000 × g for 45 min.
d
d-serine racemase activity was measured in the resuspended pellet fractions after centrifugation of lysed bacteria at 100,000 × g for 45 min.