Purification and Characterization of Griffonia simplicifolia Leaf

Leaves from mature Griffonia supficifolia plants were examined for the presence of leaf lectins possessing sugar binding specificities similar to the four known seed lectins (GS-I, GS-II, GS-III, GS-IV). Three (GS-I, -II, -IV) of the four known G. sinpIicifofia seed lectins were present in the leaves. Leaf G. simplicifolia lectins I and IV were similar to the respective seed lectins. Leaf GS-II, however, was composed of two types of subunits (Mr = 33,000 and 19,000), whereas the seed lectin consists of only one type of subumit (Mr 32,500). Seed and leaf GS-II lectins also had different isoelectric points. All leaf and seed lectins were similar with respect to their hemagglutination and glycoconjugate precipitation properties and all subunits contained covalently bound carbohydrate. Leaf GS-IV appeared slightly under-glycosylated compared to seed GS-IV. The fate of GS-I and GS-II seed lectins in aging cotyledons was investigated. GS-I isolectins usually contain isolectin subtypes associated with each main isolectin. Upon inbibition and germination, these GS-I isolectin subtypes disappeared. Over time, GS-II lectin did not change its disc gel electrophoretic properties. Griffonia simplicifolia (previously called Bandeiraea simplicifolia; 17) is a perennial woody shrub which grows in the tropical rain forests of West Africa to a height of 3 m (13, 14). The seeds of this leguminous plant contain four distinct lectins (GS5-I, GSII, GS-III, GS-IV) each with a different sugar binding specificity (9, 10). GS-I consists of five tetrameric isolectins (A4, A3B, A2B2, AB3, B4). A4 and B4 exhibit a primary sugar specificity for a-D-GalNAc and a-D-Gal, respectively, while A3B, A2B2, and AB3 possess both binding activities. GS-II is a tetrameric protein composed of a single type of subunit (4, 25) and is specific for GlcNAc residues. GS-III and GS-IV, both composed of two types of subunits, have N-acetyl-D-galactosamine and Leb (Lewis b) sugar binding activ' Supported by grant GM 29470 from the National Institutes of Health. This work was part of a dissertation submitted by J. E. L. to the faculty of the University of Michigan in partial fulfillment of the requirements for the degree of Ph.D. 2Present address: Department ofPathology, University ofUtah Medical Center, Salt Lake City, UT 84112. 3Present address: Osaka University Dental School, Nakanoshima, Kita-