Pectinase Inhibitors in Pears

In the sap of several varieties of pears a thermolabile inhibitor for the enzyme pectinase is found. The inhibitor can be isolated by precipitation with acetone. The inhibition of the enzyme increases with increasing amounts of the inhibitor up to a maximum, above which no further increase in inhibition is found. The rate of the residual breakdown of the pectin is influenced by the properties of the substrate. Evidence from the experiments points to the existence of different kinds of pectinase.