Biochemical and enzymatic properties of a fibrinolytic enzyme purified from Pleurotus eryngii cultivated under solid-state conditions using corn cob as energy source were investigated. The molecular mass of the enzyme was estimated to be 14 kDa by SDS-PAGE. The enzyme exhibited the highest activity (28.96 mol/min/mg) for the substrate tosyl-Gly-Pro-Lys-p-nitroanilide. K(m) and V(max) values were 0.18 mM and 53.5 U/ml, respectively. The enzyme was completely inhibited by 1.0 mM phenylmethylsulfonyl fluoride (PMSF). The N-terminal sequence was A-M-D-S-Q-T-D-A-S-Y-G-LA-N-D. This sequence exhibited a high degree of similarity to the N-terminal sequences of the subtilisin-like serine proteases. The enzyme was very stable at pH 4.0-6.0 with an optimum pH 5.0 at 40 degrees C. The enzyme rapidly hydrolyzed the A alpha-chain of fibrinogen within 5 min of incubation, followed by the B beta-chain after 10 min. The fibrinolytic enzyme from P. eryngii cultivated under solid-state conditions using corn cob could be potentially exploited in thrombolytic therapy.
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