TABLE 1.
Activity of ΔN54SppATk towards various peptidyl-MCA substratesa
| Substrateb | Sp act (μmol mg protein−1 min−1)
|
|
|---|---|---|
| pH 10.0 (%) | pH 8.0 | |
| Ala-Ala-Phe-MCA | 9.80 (100) | 4.70 |
| Glt-Ala-Ala-Phe-MCA | 2.85 (29) | 0.98 |
| Z-Val-Lys-Met-MCA | 1.05 (11) | 0.05 |
| Phe-MCA | 0.15 (1.5) | 0.04 |
| Suc-Ala-Ala-Ala-MCA | 0.06 (0.6) | 0.04 |
| Suc-Ile-Ile-Trp-MCA | 0.03 (0.3) | n.d. |
| Suc-Leu-Leu-Val-Tyr-MCA | 0.02 (0.2) | 0.03 |
| Ala-MCA | n.d. | 0.04 |
| Suc(OMe)-Ala-Ala-Pro-Val-MCA | n.d. | 0.01 |
| Suc-Ala-Ala-Pro-Phe-MCA | n.d. | 0.01 |
| Z-Leu-Leu-Glu-MCA | n.d. | n.d. |
| Z-Ala-Ala-Asn-MCA | n.d. | n.d. |
| Z-Leu-Leu-Leu-MCA | n.d. | n.d. |
| Z-Leu-Arg-Gly-Gly-MCA | n.d. | n.d. |
a
Activities were examined with a substrate concentration of 300 μM in 50 mM CHES (pH 10.0) or 50 mM HEPES (pH 8.0) at 60°C. n.d., activity not detected.
b
Suc, N-succinyl; Suc(OMe), N-methoxysuccinyl.