3.7 PpINH1 inhibition of PpVIN2 is affected by pH and
temperature
As shown in Figure 5i , PpINH1 inhibition of PpVIN2 occurs over
a pH range from 3.2 to 6.0, with maximum inhibition at pH 4.4
(Figure 5j ), close to the optimum pH for VIN activity (pH 4.5).
Inhibition gradually weakens at pH values in excess of 5.2.
PpINH1 inhibition of PpVIN2 activity was also measured at temperatures
ranging from 25 °C to 55 °C (Figure 5k ). As shown inFigure 5l , inhibition was greatest at 35 °C (Figure
5l ) and weakened rapidly as temperatures increased. These results
demonstrate that PpINH1 is a potent inhibitor of PpVIN2 activity, and
that inhibition varies with pH and temperature in vitro .