lectine

Lectins, also known as lectines in some languages, are a diverse group of carbohydrate-binding proteins found in many organisms, especially plants. They recognize specific sugar structures on glycoproteins and glycolipids, enabling them to mediate cell–cell interactions, protein sorting, and endocytosis. Because of their sugar-binding properties, lectins can cause agglutination of red blood cells and other cell types in laboratory assays.

Lectins are abundant in seeds and fruits as part of plant defense, and they vary widely in their carbohydrate specificities. Well-known plant lectins include concanavalin A (ConA) from jack beans, phytohemagglutinin (PHA) from red beans, and several seed lectins with diverse sugar affinities. Ricin, a highly toxic plant protein from castor beans, contains a lectin-like B-chain that binds galactose and facilitates toxin entry.

In biology, lectins participate in processes such as cell recognition, differentiation, and immune interactions. In animals, some lectins modulate gut immune responses and serve as lectin receptors that shape cellular trafficking. In biotechnology, lectins are used for affinity purification of glycoproteins, lectin arrays for glycan profiling, and in blood typing (various lectins bind specific blood group antigens).

Dietary considerations reflect both beneficial and adverse aspects. Some lectins are thermolabile and are inactivated by cooking, while others can be toxic if consumed raw in significant amounts. The health impact of dietary lectins is a topic of ongoing research; broad dietary avoidance is not routinely recommended for the general population.