2.4. Kinetics study of ˛-glucosidase
The most active fractions showing the lowest IC50 value of
S. arenaria were tested to find the type of inhibition exerted
on -glucosidase. The reaction mixture was as described above,
except that the substrate concentration varied from 0.3 to 5 mM,
and that of the extract was kept constant at 1.25 mg/ml. The
reaction was started by the addition of enzyme, and monitored
at 405 nm, at 5 min intervals during 30 min. The initial reaction
rates were determined using calibration curves constructed using
varying p-nitrophenol concentrations The results were used to construct
Lineweaver–Burk plots to determine the type of inhibition,
Michaelis–Menten constant (KM) and maximum velocity (Vmax)
values.