Isolation and characterization of soybean insulin-binding proteins
S. F. Barbashov, Ts. A. Egorov, V. M. Kochkina
V. A. Engelhardt Institute of Molecular Biology, Academy of Sciences of the USSR, Moscow
Abstract: Two soybean insulin-binding proteins were isolated using affinity chromatography on insulin-Sepharose. Both proteins have molecular mass about 39 kDa and consist of two subunits linked by disulphide bonds. According to the amino acid composition and N-terminal sequences of the subunits, these proteins, characterized by the absence of free thiol groups and sugar residues, are variants of the previously described soybean basic 7S globulin. The blotted proteins as well as their subunits were shown to bind 125I-labelled bovine insulin. For one of the proteins and insulin, dissociation constant of 4·10-9 M was measured. The existence of plant insulin-binding proteins suggests the insulin-like' regulation in the plant metabolism.
Russian Journal of Bioorganic Chemistry 1991, 17 (3):421-423