Occurrence of dissociable and undissociable soybean glycinin.

Glycinin was dialyzed against low ionic strength buffer (μ=0.01) and centrifuged in sucrose density gradient. Two major components with the sizes of 7S and 11S were obtained. When each component was separately recentrifuged, the intrinsic peak of each was predominantly given. This indicates that there were two molecular species in the glycinin, one being dissociable and the other undissociable at low ionic strength. The dissociable species reversibly associated to the size of 1 IS at high ionic strength. The conformation of each species was different, the dissociable species being more random and unstable than the undissociable species at low ionic strength. The dissociable species contained more ASIV and less ASIII than the undissociable species.