Table 2.
Specific activities and substrate specificities of N. aromaticivorans and E. coli ld-carboxypeptidasesa
| Substrate | Sp act (nmol/min/mg) |
|
|---|---|---|
| NaLdcA | EcLdcA | |
| l-Ala-γ-d-Glu-meso-A2pm-d-Ala | 230,000 | 250,000 |
| UDP-MurNAc-l-Ala-γ-d-Glu-meso-A2pm-d-Ala | 24,500 | 65,500 |
| UDP-MurNAc-l-Ala-γ-d-Glu-meso-A2pm-d-Ala-d-Ala | 7 | 51 |
| GlcNAc-MurNAc(anhydro)-l-Ala-γ-d-Glu-meso-A2pm-d-Ala | 14,300 | 26,500 |
| MurNAc-l-Ala-γ-d-Glu-meso-A2pm-d-Ala | 30,000 | 35,500 |
| MurNAc-l-Ala-γ-d-Glu-l-Lys-d-Ala | 1,000 | 450 |
a
The standard enzyme assay conditions described in Materials and Methods were used. The amount of enzyme varied from 0.2 ng to 0.5 μg, depending on the substrate used. To ensure linearity, the consumption of substrate was <20% in all cases. Values represent the means for three experiments; the standard deviation was <10% in all cases.