Biochemical characterization of amandin, the major storage protein in almond (Prunus dulcis L.)

The almond major storage protein, amandin, was prepared by column chromatography (amandin-1), cryoprecipitation (amandin-2), and isoelectric precipitation (amandin-3) methods. Amandin is a legumin type protein characterized by a sedimentation value of 14S. Amandin is composed of two major types of polypepticles with estimated molecular weights of 42-46 and 20-22 kDa linked via disulfide bonds. Several additional minor polypepticles were also present in amandin. Amandin is a storage protein with an estimated molecular weight of 427,300 47,600 Da (n = 7) and a Stokes radius of 65.88 +/- 3.21 Angstrom (n = 7). Amandin is not a glycoprotein, Amandin-1, amandin-2, and amandin-3 are antigenically related and have similar biochemical properties. Amandin-3 is more negatively charged than either amandin-1 or amandin-2. Methionine is the first essential limiting amino acid in amandin followed by lysine and threonine.