PROPERTIES AND DISTRIBUTION OF SOYBEAN PROGLYCININ EXPRESSED IN SACCHAROMYCES-CEREVISIAE

Glycinin is a predominant storage protein of soybean. The high-level expression system of preproglycinin cDNA in yeast was established. The signal sequence of the expressed protein was cleaved at the correct site. However, most of the expressed proteins were insoluble due to their interaction with intracellular components at the acidic polypeptide region. The expressed proteins separated from the intracellular components by ion-exchange chromatography in the presence of urea were soluble without urea and self-assembled into trimers. The insolubility of the expressed proteins caused an accumulation of modified proteins with disturbed folding. Immunocytochemical distribution demonstrated that the expressed protein from the cDNA encoding preproglycinin accumulated in Golgi-like structure and organellas which may be derived from Golgi-like structure, and one from the cDNA encoding proglycinin homologue protein was found in the cytosol.