Substrate | mU/mg protein (%) | kcat (min−1) | Km (μm) | kcat/Km (mm−1/min) |
---|---|---|---|---|
Ac-SLR-MCA | 241 (177) | 20.7 | 162 | 128 |
Boc-VPR-MCA | 136 (100) | 12.8 | 77.0 | 166 |
Ac-KDR-MCA | 94.1 (69.2) | 17.2 | 550 | 31.2 |
Ac-KER-MCA | 61.5 (45.2) | 2.70 | 550 | 16.7 |
Ac-ELR-MCA | 11.3 (8.31) | 4.16 | 332 | 12.5 |
Ac-DVR-MCA | 0.55 (0.40) | 1.34 | 380 | 3.54 |
Ac-YGR-MCA | 0.0014 (0.001) | 0.57 | 247 | 2.31 |
Fluorogenic peptide substrates with an MCA leaving group were used to determine enzyme activity and kinetic parameters. One unit of activity hydrolyzes 1 μmol chromogen/min. Percentages of the activity against Boc-VPR-MCA are shown in parentheses; Ac-SLR-MCA was the best synthetic substrate for neuropsin.