LOCALIZATION AND GENERAL-PROPERTIES OF DEVELOPING PEACH SEED COAT ANDENDOSPERM PEROXIDASE ISOENZYMES

Changes of soluble and ionically bound peroxidase and indoleacetic aci d (IAA) oxidase activities were followed during peach seed development . Soluble peroxidase activity was located mainly in the embryo plus en dosperm tissue, whereas wall ionically bound activities were found pre dominantly in the integument tissue. The different peroxidase isoenzym es present in the extracts were characterized by polyacrylamide gel el ectrophoresis and isoelectric focusing; the main soluble isoenzyme of embryo plus endosperm tissue was an anionic isoperoxidase of R-F 0.07. Basic ionically bound isoenzymes were located only in the integument tissue, but two soluble anionic isoenzymes of R-F 0.23 and 0.51 were a lso present in this tissue, In parallel, peroxidase protein content wa s estimated specifically using polyclonal antibodies, The kinetic data and the changes of seed IAA oxidase activity during fruit development suggested that basic peroxidase isoenzymes from ionically bound extra cts of integument might be involved in IAA degradation.