Table 6.

Kinetic parameters for human urinary kallikrein (hK1) and wild-type and mutated (R53H and Q121E) recombinant kallikreins

Abz-FRSSRQ-EDDnpad-PFF-NMecbBovine Kininogen
Km (μM)kcat (min−1)kcat/Km (μM−1 · min−1)Km (μM)kcat (min−1)kcat/Km (μM−1 · min−1)Km (μM)kcat (min−1)kcat/Km (μM−1 · min−1)
a Fluorogenic substrate mimicking the carboxy-terminal cleavage site of kininogen (o-aminobenzoic acid-FRSSRQ-ethylenediamine 2, 4 dinitrophenyl).
b Fluorogenic chimeric amidated substrate derived from the carboxy-terminal sequence of bradykinin and the kallistatin loop (D-PFF-7 amino 4 methyl conmarin).
c Kininogen hydrolysis was too slow to allow determination of kinetic parameters.
hK13.66 ± 1.179.04 ± 0.962.477.27 ± 1.8083.7 ± 7.211.51.71 ± 0.7256.8 ± 15.833.2
Wild-type1.83 ± 0.511.0 ± 0.96.017.37 ± 3.5030.7 ± 3.84.27.86 ± 4.0076.0 ± 34.79.7
Q121E1.91 ± 0.362.25 ± 0.11.186.69 ± 3.7514.0 ± 2.02.11.93 ± 0.4462.4 ± 9.632.3
R53H43.6 ± 9.50.09 ± 0.010.00289.2 ± 23.711.3 ± 0.20.13ccc