Subcellular Localization of a Basic Peroxidase Isoenzyme in Crisphead Lettuce

Abstract

The subcellular localization of a basic peroxidase (EC 1.11.1.7) isoenzyme in crisphead lettuce (Lactuca sativa L.) leaves was studied through subcellular fractionation and protoplast and vacuole isolation. This isoenzyme is mainly located in soluble fractions. Studies using protoplast isolation and vacuole purification indicated that the soluble basic peroxidase isoenzyme is found in the vacuolar sap, probably in equilibrium with the same isoenzyme attached to tonoplast membranes.