Lectin from bean seeds

Ricin was found by Stillmark in 1889 as the first plant lectin derived from the seeds of the castor plant, Ricinus communis L., a member of the Euphorbiaceae or spurge family. Other members of this family include the popular houseplants poinsettia E. pulcherrima), and the croton species. The term castor bean is used commonly to refer to both the plant and seed of R. communis. Ricinus communis commonly grows along streams and riverbeds in addition to subtropical locations high in nutrients. Ricinus communis is a coarse perennial, 10-13 m tall in the tropics, with a stem 7.5-15 cm... 

These proteins occur in the seeds of many plants but are especially common in the Fabaceae (Leguminosae) (more than 600 species) and the Euphorbiaceae (lectins also occur in other organisms such as fungi, bacteria, and animals). In legumes, lectins are usually found in the cotyledons (Liener, 1991). Well-known plant lectins are concanavalin A, from jack beans Canavalia ensiformis), favin, from the broad bean (Vida faba), and phasin, from the kidney bean (Phaseolus vulgaris) (Ramshaw, 1982), The toxicity of lectins differs considerably (Liener, 1991 Liener et al, 1986). Data for lectins are given in Liener et al. (1986) and Lis and Sharon (1981). 

The starting material for the preparation of plant lectins is usually the seeds. They are either collected in the field or purchased from commercial sources. In some cases, seed meal is also available (e.g., jack bean or soybean flour). 

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