ABSTRACT
Lectins are proteins that bind to carbohydrates and sugar containing substances in a specific and reversible way or precipitate glycoconjugates. These heterogeneous class of carbohydrate-binding proteins or glycoproteins of non-immune origin are capable of specific recognition of, and reversible binding to, carbohydrates without altering their covalent structure. Lectins are found in a diversity of organisms and possess the ability to agglutinate erythrocytes with known carbohydrate specificity since they have at least one non-catalytic domain that binds reversibly to specific monosaccharides or oligosaccharides. This review aims to highlight the applications of lectins in various fields of biology. Lectins are isolated from their natural sources by chromatographic procedures with various modulations to increase their production. The yields of animal lectins are usually low compared with the yields of plant lectins such as legume lectins, which form a major source of these proteins. Lectins manifest a diversity of activities including anti-insect activities, antitumor, immunomodulatory, antimicrobial and HIV-1 reverse transcriptase inhibitory, which may find applications in many therapeutic areas. A small number of lectins demonstrate anti-parasitic activities.