Table 2. Kinetic parameters of popular HIV-1 protease substrates and substrate 1.

Substrate	kcat (s−1)	KM (μM)	kcat/KM (μM−1s−1)	If/Io	Sa (μM−1s−1)
DABCYL-SQNYPIVQ-EDANSb	4.9 ± 0.2	103 ± 8	0.048 ± 0.004	40	2
Abz-TINleF(p-NO2)QR	8.2 ± 0.4c	13 ± 1c	0.63 ± 0.06	6d	4
Substrate 1e	7.4 ± 0.2	14.7 ± 1.0	0.50 ± 0.04	104	52

^aSensitivity: S = (k_cat/K_M)(I_f/I_o).

^bValues ( ± SD) are from ref. 12.

^cValues ( ± SE) are from ref. 16.

^dValue is from ref. 11.

^eValues ( ± SE) are from this work.