Table 2. Characterization of the purified NHases, α(StrepP14K)2, R-NHases and R-α(StrepP14K)2.
| Protein (plasmid) | NHase activity, units/mg | Co content (mol of ions/mol of protein) | N-terminal sequence of α-subunit |
| Holo-NHase (pET-A-B-P14K) | 439±3.6 | 0.88±0.06/αβ | GQSHTHD |
| Apo-NHase (pET-A-B-P14K) | 18.3±3.2 | 0.03±0.01/αβ | ND* |
| Holo-NHase (pET-A-B-StrepP14K) | 421±6.0 | 0.89±0.05/αβ | ND |
| Holo-α(StrepP14K)2 (pET-A-B-StrepP14K) | 0 | 0.91±0.01/α(StrepP14K)2 | GQSHTHD |
| Apo-α(StrepP14K)2 (pET-A-B-StrepP14K) | 0 | 0.04±0.01/α(StrepP14K)2 | ND |
| R-apo-NHase | 418±5.8 | 0.87±0.05/αβ | ND |
| R-α(StrepP14K)2 (pET-A-B-StrepP14K) | 0 | 0.90±0.04/α(StrepP14K)2 | ND |
| Holo-NHase(HisT7-α) (pET-HisT7A-B-P14K) | 396±8.7 | 0.89±0.05/αβ | ND |
| Apo-NHase(HisT7-α) (pET-HisT7A-B-P14K) | 20.5±4.9 | 0.04±0.02/αβ | GSSHHHH |
| R-NHase(HisT7-α) | 417±8.0 | 0.87±0.03/αβ | GQSHTHD |
| Holo-NHase (pET-B-A-P14K) | 410±6.3 | 0.89±0.05/αβ | ND |
*
ND, not detected.
The corresponding expression plasmids are shown in parentheses.