Cereal Chem 63:332-335   |  VIEW ARTICLE
Isolation and Properties of a Thiamine-Binding Protein from Buckwheat Seed.

T. Mitsunaga, M. Matsuda, M. Shimizu, and A. Iwashima. Copyright 1986 by the American Association of Cereal Chemists, Inc. 

A thiamine-binding protein was isolated from buckwheat seeds by extraction with 0.05M phosphate buffer (pH 7.0, containing 1% NaCl), fractionation with ammonium sulfate, ion-exchange chromatography on a diethylaminoethyl-Sephadex A-25 column, and gel filtration on a Sephacryl S-300 column. The final preparation was homogeneous by gel electrophoresis and had an apparent molecular weight of 140,000 as estimated by gel filtration. The apparent Kd and Bmax of binding for [14C] thiamine were 1.1 microM and 6.94 nmol/mg of protein, respectively. The optimal pH for binding was 8.5. Competition experiments using several thiamine derivatives suggested high binding specificity of the protein for thiamine.