KINETICS OF THE HYDROLYSIS OF L-GAMMA-GLU-PARANA BY DESTABILASE, AN ENZYME FROM THE LEECH HIRUDO-MEDICINALIS

The molecular weight (12.3 kD) was determined for the enzyme destabilase, isolated from the medicinal leech Hirudo medicinalis. An investigation of the kinetics of the hydrolysis of the only synthetic substrate known at present, L-gamma-Glu-pNA,* showed that the enzyme is rather stable, withstanding 5 min heating at 70-degrees-C; the optimum pH lies in the region of 7.0-8.5. For the enzyme with specific activity 0.15.10(-9) mole/sec.mg the values K(m) = 22.10(-4) M and K(cat) = 3.53.10(-3) sec- at 37-degrees-C, pH 8.0 were determined.