Peanut and horse radish peroxidase isoenzymes. Intraspecies and interspecies immunological relatedness

Abstract The presence of structural similarities in peroxidase isoenzymes was demonstrated by the technique of crossed immunoelec‐trophoresis. Isoenzymes found in the medium of peanut (Arachis hypogaea L.) cells grown in suspension culture were immuno‐precipitated in different arc systems according to the extent of relatedness of their antigenic determinants. Cross reactivity between isoenzymes in the medium was confirmed by demonstration that antibodies raised against only the glycoprotein fraction of the medium peroxidases would react also with the non‐glycosylated peroxidase isoenzymes that did not have affinity for Concanavalin A. Different peroxidase isoenzsmes from peanut leaves, peanut calli and peanut suspension cell medium share common antigenic determinants. Antibodies against peroxidase antigens from a different species, horse radish (Armoracia lapathifolia Gilib.), reacted with peroxidase antigens in the peanut cell medium. The results suggest a similarity of peanut peroxidases to horse radish peroxidase and. therefore, an evolutionary conservatism in peroxidase structure. The results also point to the potential utility of immunochemistry, including microcomplement fixation, to quantitate the structural similarities of peroxidase isoenzymes.