Characterization of a soybean cultivar lacking certain glycinin subunits.
The 11S storage protein (glycinin) of soybean [Glycine max (L.) Merr., cv. Raiden] was studied by polyacrylamide gel electrophoresis and amino acid sequence analysis. It contained the following subunits composed of acidic (A) and basic (B) polypeptides: A1aB2, A1bB1b, A2B1a, and A3B4. However, it lacked polypeptides A4, A5, and B3 which are present in many other cultivars. A new acidic polypeptide called A6 was present in a low amount and was characterized by amino acid sequence analysis. It was homologous to A4, although of a smaller apparent molecular weight. Since Raiden has an average protein content of about 40% and its glycinin fraction can be purified as a 350,000 D complex which is typical of other cultivars, the results imply polymorphism with respect to glycinin subunit composition. Because there is a wide variation in the methionine content of the various subunits, these findings suggest the possibility of genetically manipulating the nutritional quality of soybean seed protein by altering glycinin subunit composition.
D000595:Amino Acid Sequence; D005916:Globulins / Q000032:analysis*; D007526:Isoelectric Point; D046911:Macromolecular Substances; D014674:Plant Proteins, Dietary / Q000032:analysis*; D011487:Protein Conformation; D030262:Soybean Proteins; D013025:Glycine max / Q000032:analysis* / Q000235:genetics
D005916:Globulins; D046911:Macromolecular Substances; D014674:Plant Proteins, Dietary; D030262:Soybean Proteins; C011474:glycinin