A serine protease in soybean seeds that acts specifically on the native alpha subunit of beta-conglycinin.
A proteolytic activity directed against the alpha subunit of beta-conglycinin was detected in resting mature seeds of the soybean [Glycine max (L.) Merrill] cultivar Keburi. The relationship between pH and activity and the effect of protease inhibitors revealed that the enzyme was a neutral/alkaline serine protease. The proteolysis of the alpha subunit of beta-conglycinin yielded a specific product with a molecular weight of about 47,000, as determined by SDS-PAGE, but the enzyme had no activity against the beta subunit. The amino acid composition, the molecular weight and the amino-terminal amino acid sequence of the proteolytic product revealed that the action of the enzyme on the alpha subunit was specific, with cleavage occurring only at the R126-R127 peptide bond of the alpha subunit. These characteristics of the protease indicate that the enzyme is a novel protease that has not previously been recognized in soybean seeds.
Morita
S
S
Central Research Institute, Fuji Oil Co., Ibaraki, Japan.
Fukase
M
M
Hoshino
K
K
Fukuda
Y
Y
Yamaguchi
M
M
Morita
Y
Y
D000595:Amino Acid Sequence; D000596:Amino Acids / Q000032:analysis; D052179:Antigens, Plant; D005916:Globulins / Q000737:chemistry / Q000378:metabolism*; D008969:Molecular Sequence Data; D011480:Protease Inhibitors; D055314:Seed Storage Proteins; D012639:Seeds / Q000201:enzymology*; D017421:Sequence Analysis; D012697:Serine Endopeptidases / Q000302:isolation & purification / Q000378:metabolism*; D030262:Soybean Proteins; D013025:Glycine max / Q000201:enzymology*
D000596:Amino Acids; D052179:Antigens, Plant; D005916:Globulins; D011480:Protease Inhibitors; D055314:Seed Storage Proteins; D030262:Soybean Proteins; C013894:beta-conglycinin protein, Glycine max; D012697:Serine Endopeptidases