Protein Bodies from Buckwheat Seed Cotyledons: Isolation and Characteristics

Protein bodies were isolated from cotyledons of dry buckwheatseeds by homogenization in acetone with subsequent purificationin a 1.26 g cm^–3 to 1.53 g cm^–3 linear density gradientof a mixture of acetone with CCI₄. The purified fraction ofprotein bodies with globoids (PB I) had a buoyant density of1.48–1.51 g cm^–3 and was intact according to microscopicdata. Localization of hydrolytic enzymes and proteinase inhibitorsin the PB I fraction and in the fraction of the cytoplasm andmembrane material (CMM) was studied. It was shown that acidhydrolytic enzymes, such as aspartic proteinase, carboxypeptidase,acid phosphatase, -D-mannosidase and N-acetyl-ß-glucosaminidase,as well as chymotrypsin and trypsin inhibitors were predominantlylocalized in the PB I. BAPAase and SH-activated caseinase activitieswere equally distributed between the PB I and CMM fraction.The activities of leucine aminopeptidase and SH-independentcaseinase were noticeably predominant in the CMM fraction. Key words: Buckwheat, subcellular fractionation, protein bodies, hydrolases