ISOLATION AND CHARACTERIZATION OF DIOCLEA-ALTISSIMA VAR MEGACARPA SEED LECTIN

A lectin was isolated from Dioclea altissima var. megacarpa seeds by a ffinity chromatography on Sephadex G-50 column. The lectin showed carb ohydrate specificity for D-mannose/D-glucose, and divalent metal catio ns (Ca2+ and Mn2+) are required for full activity. It contained no cov alently bound carbohydrate and had an amino acid composition character ised by large contents of aspartic acid and serine. The activation ene rgy of the heat denaturing process was 106.9 kJ mol(-1). The lectin pr esented three protein bands in SDS-PAGE, with M-r of 26 000, 15 000 an d 9000, respectively, and showed immunological identity and the same N -terminal sequence as other lectins already isolated from the sub-trib e Diocleinae. (C) 1997 Elsevier Science Ltd. All rights reserved.