Table 2. Kinetic parameters for hydrolysis of substrates 1–8 by recombinant human renin, increase of fluorescence intensities and quenching efficiencies.

Hydrolysis conditions: 50 mM Mops/NaOH, pH 7.0, 2 mM EDTA, 0.5% BSA, 0.1% NaN₃ and 1% DMSO at 37 °C. Fluorescence was measured at excitation and emission wavelengths of 328 nm and 388 nm respectively. q.e., quenching efficiency.

Substrate	kcat/Km (M−1·s−1)*	F1/F0	q.e. (%)	kcat (s−1)†	Km (μM)†
1	No hydrolysis	−	−	−	−
2	16000	–‡	−	0.02	2.30
3	41000	12	92	0.20	4.45
4	29000	18	94	0.11	4.56
5	64000	14	93	0.06	1.22
6	22000	10	90	0.02	1.49
7	96000	6	83	0.08	0.55
8	181000	5	80	0.13	0.82

* Determined via the progress-curve method under pseudo-first-order conditions.

† Determined via the initial-rate method.

‡ This value was not determined because of the high fluorescence of the intact substrate solution, caused by impurities.