Abstract
A lectin-like protein was isolated and purified from etiolated cowpea hypocotyls with a galactose-immobilized chromatography under a monitoring of the lectin activity with hemagglutination tests using trypsinated rabbit red blood cells. The protein was estimated about 25 kD on the basis of its behavior on SDS-PAGE, and temporarily named Vigna lectin 25(VL25).
The lectin activity of the VL25 was inhibited by a galactose-addition into the reaction buffer, and had a strong pH-dependency; VL25 agglutinated the red blood cells under pH7, but not under pH below pH5.
A western blotting analysis using anti-yieldin rabbit antiserum suggested that VL25 was a part or a homologue of yieldin, a protein regulating the yield threshold.
These data suggested VL25 to play some roles in the regulation mechanism of the yield threshold via its lectin activity binding to galactose residues of wall polysaccharides, and could be a clue to clarify the reaction mechanism of yieldin.
