Table I.

Comparison of the effects of a range of protease inhibitors on the activity of purified soybean Ser protease in vitro and on the oxidative burst in vivo

Inhibitor	Protease Activity		Oxidative Burst
	Inhibitor concentration	Protease activity	Control	Yeast elicitor
	μm	%	μm H2O2
Control (DMSO)	0	100	0.00  ± 0.10	2.10  ± 0.44
Antipain	20	0	4.55  ± 0.43	13.2  ± 1.17
DCIa	1000	26	1.03  ± 0.27	12.4  ± 1.49
DFP	1000	2	1.34  ± 0.17	9.46  ± 1.03
Leupeptin	15	0	0.13  ± 0.11	5.90  ± 0.34
PMSF	1000	81	0.11  ± 0.06	12.4  ± 1.41
TLCKb	1000	61	0.10  ± 0.13	3.52  ± 0.22
TPCKc	1000	47	5.86  ± 0.60	8.90  ± 1.07

Concentrations of inhibitors used in vitro are given. Inhibitors were applied to cells at a final concentration of 0.5 mm (0.2 mm for antipain), and H₂O₂ was measured 2 h after exposure to water (control) or yeast elicitor (200 μg Glc equivalents mL⁻¹). Results show the average ± sd from three independent experiments.

^aDCI, 3,4-dichloroisocoumarin. 

^bTLCK, Nα-p-tosyl-l-lysine chloromethyl ketone. 

^cTPCK, n-tosyl-l-phenylalanine chloromethyl ketone.