One- and two-dimensional gel electrophoresic identification of African yam bean seed proteins.

Seed proteins were extracted from the African yam bean (AYB; Sphenostylis stenocarpa), an underutilized West African food legume. One- and two-dimensional polyacrylamide gel electrophoresis was then used to analyze the albumin fraction, galactose-specific lectins purified on immobilized galactose-Sepharose 4B, and abundant non-lectin seed proteins left over following affinity chromatography. N-terminal sequencing of prominently resolved polypetide bands led to identification of proteins having sequence homology with characterized legume seed proteins, namely, mung bean seed albumin, pea alpha-fucosidase, soybean Kunitz-type trypsin inhibitor, an endochitinase, pea pathogenesis-related protein, and/or cowpea seed storage proteins. Minor lectin-like proteins lacking hemagglutinating activity against rabbit and human erythrocytes were also identified. Because proteins such as protease inhibitors, chitinases, pathogenesis-related proteins, and lectins are known to have antimetabolic effects, the findings from this study may have relevance in the acceptability, adoption, and utilization of AYB as human food.