Purification and characterization of the acid soluble 26-kDa polypeptide from soybean seeds.
Whey proteins from soybean seeds of Japanese varieties were analyzed by SDS-polyacrylamide gel electrophoresis (SDS-PAGE). Among 11 varieties of soybean, three green and one black soybeans lacked a 26-kDa band that was found in all yellow soybeans. In this paper, the 26-kDa protein was named AS26k (acid soluble 26-kDa protein) temporarily. The AS26k protein was purified from Glycine max cv. Nattosyoryu, which is yellow soybean, through four purification steps: 30-35% saturated ammonium sulfate fractionation, ion exchange chromatography on S Sepharose Fast Flow, gel filtration on Sephadex G-100, and hydrophobic chromatography on phenyl Sepharose CL-4B. Purified AS26k was cleaved with V8 proteinase from Staphylococcus aureus or CNBr. The cleaved polypeptide contained two typical dehydrin motif sequences: DEYGNPV and (M)DKIKEKLPG, and a 19 amino acids sequence similar to a pea dehydrin. Native AS26k had a molecular mass of 32 kDa on gel filtration and a pl of 7.2 on two-dimensional PAGE. Similarly to other dehydrins and late embryogenesis abundant (LEA) proteins, AS26k was rich in hydrophilic amino acids, and highly heat stable. These results showed that AS26k was a dehydrin, a group II LEA protein in soybean seeds.
Momma
M
M
National Food Research Institute, Ministry of Agriculture Forestry, and Fisheries, Ibaraki, Japan.
Haraguchi
K
K
Saito
M
M
Chikuni
K
K
Harada
K
K
D000595:Amino Acid Sequence; D000596:Amino Acids / Q000032:analysis; D002850:Chromatography, Gel; D002852:Chromatography, Ion Exchange; D004591:Electrophoresis, Polyacrylamide Gel; D006360:Heat-Shock Proteins / Q000378:metabolism; D006358:Hot Temperature; D008969:Molecular Sequence Data; D008970:Molecular Weight; D010455:Peptides / Q000737:chemistry* / Q000302:isolation & purification; D013025:Glycine max / Q000737:chemistry*
D000596:Amino Acids; D006360:Heat-Shock Proteins; D010455:Peptides