The structure, physical and chemical properties of the soy bean protein glycinin.

The major storage protein of the soybean, glycinin, has been prepared in a homogeneous form and examined by a variety of techniques. It has been found that the protein has a molecular weight of 320000 and contains two sizes of subunits with different isoelectric points. There are six acidic subunits of approximately 35000 and six basic of approximately 20000. Analysis revealed three different kinds of acidic subunits and probably three kinds of basic ones also. These twelve subunits are packed in two identical hexagons, placed one on the other, yielding a hollow oblate cylinder of 110 X 110 X 75 A. Some or all of the subunits are non-spherical resulting in a partial blocking of the central hole. Information about the forces stabilzing the native structure is also discussed.