TABLE 4.

Kinetic constants for the catalytic reaction of furin-PC(298–300) loop chimeras with RXXR fluorogenic substrate

Kinetic parameters were determined at pH 7.5, 25 °C as in Table 2.

Furin-PC chimeras	Amino acid sequence at loop 298–300	Boc-RVRR-amc
		KM	kcat	kcat/KM	kcat/KM variant/wt ratio
		μm	s−1	m−1 s−1
Wild-type	REH	28.2 ± 1.3	0.27 ± 0.01	9.2 ± 1.0 × 103	1
F-PC1	RQG	27.6 ± 2.3	0.17 ± 0.01	6.2 ± 1.0 × 103	0.67 ± 0.18
F-PC2	SY-	20.0 ± 1.5	0.09 ± 0.01	4.6 ± 0.8 × 103	0.50 ± 0.14
F-PC4	LHY	34.3 ± 2.4	0.24 ± 0.03	7.0 ± 1.3 × 103	0.76 ± 0.22
F-PC5/6	RSK	45.7 ± 2.7	0.13 ± 0.02	2.8 ± 0.5 × 103	0.30 ± 0.09
F-PACE4	REG	27.0 ± 1.5	0.27 ± 0.01	9.7 ± 1.0 × 103	1.1 ± 0.23
F-PC7	QHN	23.9 ± 1.8	0.29 ± 0.06	1.2 ± 0.3 × 104	1.3 ± 0.47
298–300	AAA	20.5 ± 2.9	0.09 ± 0.01	4.4 ± 0.8 × 103	0.48 ± 0.14