Biochemical Aspects of a Serine Protease from Caesalpinia echinata Lam. (Brazilwood) Seeds: A Potential Tool to Access the Mobilization of Seed Storage Proteins

Table 3

Effects of some inhibitors on the CeSP activity.

Compound	Final concentration	Relative activity (%)
None	–	100
Serine protease inhibitors
TLCK	50 μM	4.30
Benzamidine	4.0 mM	57.4
PMSF	0.50 mM	69.2
SBTI	49.8 μM	71.8
Aprotinin	307 nM	89.3
CeKI	215 nM	97.2
TPCK	50 μM	119
Cystein protease inhibitor
E-64	5.0 μM	92.3
Aspartyl protease inhibitor
Pepstatin A	1.0 μM	77.6
Metallo protease inhibitor
EDTA	1.0 mM	99.7

Irreversible (PMSF, TLCK, TPCK or E-64) or reversible inhibitors (aprotinin, benzamidine, CeKI, SBTI, EDTA or pepstatin A) were tested on the hydrolysis of H-D-Pro-Phe-Arg-pNA (0.2 mM) by CeSP (50 nM) in 50 mM Tris buffer, pH 7.1, for 30 min at 37°C. The release of p-nitroaniline was followed at 405 nm.