Physicochemical Studies on the Proteins of the Peanut Cotyledon and Embryonic Axis

Abstract

Subcellular fractions from the cotyledon obtained by differential and density gradient centrifugation, and extracts of total proteins from both cotyledon and axial tissues were analyzed by diethylaminoethyl cellulose chromatography, zone electrophoresis, ultracentrifugation, immunodiffusion, and immunoelectrophoresis. Fractionation and characterization of proteins in subcellular organelles of the peanut reaffirm that α-arachin is located in the protein bodies of the cells. Results obtained by diethylaminoethyl cellulose chromatography of subcellular fractions suggest that some of the conarachin proteins are cytoplasmic. α₁-Conarachin is cytoplasmic, and α₂-conarachin is particle-bound. α-Arachin and α₂-conarachin predominate in the cotyledon. Quantitative differences for other proteins were also observed. Although qualitative similarities are apparent by immunoelectrophoresis, major differences were observed in the sedimentation patterns, zone electrophoreograms, and in the diethylaminoethyl cellulose chromatograms of total protein extracts from the cotyledon and the axis.