[Kinetics of L-gamma-Glu-pNA hydrolysis by destabilase, the enzyme from the medicinal leech Hirudo medicinalis].

The molecular mass of destabilase isolated from the medicinae leech Hirudo medicinalis was found to be equal to 12.3 kDa. A kinetic analysis of the sole presently known synthetic substrate, L-gamma-Glu-pNA, showed that the enzyme is relatively stable to heating (5 min, 70 degrees C); the pH optimum lies at 7.0-8.5. The enzyme has a specific activity of 0.15 x 10(-9) mol.s-1.mg-1; Km = 2.2 x 10(-4) M, kcat is 3.53 x 10(-3) s-1 (pH 8.0, 37 degrees C).