isolectin

Isolectin is a term used for a variant form of a lectin that originates from the same gene family or plant species but differs in carbohydrate-binding specificity. Isolectins arise from genetic variation, alternative splicing, or different plant lines and are closely related but not identical in binding properties. While all lectins bind specific carbohydrate structures, isolectins may recognize related glycans with different affinities or select for different linkages, enabling researchers to distinguish subtle differences in glycosylation. Many isolectins require divalent metal ions such as calcium and manganese for carbohydrate binding, and their activity can be influenced by pH and buffer composition.

Examples of isolectin families are those derived from Bandeiraea simplicifolia and Griffonia simplicifolia, which have been profiled into multiple isolectins used in histology and glycoprotein studies. Isolectins are commonly employed as histochemical tools to map glycan distribution on cells and tissues, and in affinity purification and glycan profiling platforms such as lectin microarrays. They can also be used to separate glycoproteins on chromatography columns by carbohydrate affinity.

In summary, isolectins are related variants of lectins that expand the repertoire of carbohydrate recognition used in glycobiology. They are distinguished from other lectin forms by their specific sugar-binding profiles and often by their molecular forms and tissue origins.