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Hemagglutinin lateral

Lectins are complex proteins or glycoproteins that bind specific carbohydrate structures and are therefore able to bind specifically to cells or cell membranes and trigger biochemical reactions from there. However, they do not have any enzymatic activity.

Lectins ( Latin legere , reading ',' select '), various metabolic processes such as cell division , the ribosomal protein biosynthesis , the agglutination of cells (in terms of red blood cells is a hemagglutination ) or the immune system ( Ficoline influence).

Lectins are common. They can be produced by animals, plants or microorganisms.


The lectins include N- acetylglucosamine -binding Gramineae- lectins, the chitin -binding Solanaceae- lectins, the group of legume lectins and the mannose -binding lectins from Amaryllidaceae , Alliaceae and Orchidaceae . The lectins from Aegopodium podagraria and Urtica dioica have not yet been assigned to any group. Many other lectins are also known.

Lectins also include some AB toxins such as B. high-molecular seed glycoproteins such as ricin or such as the bacterial toxins Shiga toxin , Vero toxin , diphtheria toxin , exotoxin A or alpha-sarcin . Abrin , ricin , phasine (after Phaseolus vulgaris , the common bean : Red kidney bean lectin, erythroagglutinin, PHA-E, Phaseolin ) and IgSF ( English I-type lectins 'I type lectins'), calnexin and calreticulin are different lectins. An example of a lectin without sugar residue is Concanavalin A from the seeds of the jack bean Canavalia ensiformis .

Lectin names, occurrences and functions
designation Organisms physiological function particularities Carbohydrate specificity
Abrin Abrus precatorius
alpha-sarcin Aspergillus giganteus mold Translational inhibition toxin
Calnexin Chaperone
Calreticulin Chaperone
Concanavalin A Jack bean without sugar residues α-D-mannosyl and α-D-glucosyl residues
Diphtheria toxin Corynebacterium diphtheriae Penetration into cells and translation inhibition diphtheria
Exotoxin A Pseudomonas aeruginosa Penetration into cells toxin
IgSF Mammals
Lentil lectin (LCH) Lens culinaris Mannosylated fucose
Mitogillin Aspergillus restrictus mold Translational inhibition toxin
Phasins Kidney bean , chickpea Agglutinins Hemagglutination , toxin, heat deactivatable
Winterling lectin Winterling Eranthis hyemalis Translational inhibition Type II ribosome-inactivating protein N-acetyl-D-galactosamine
Peanut agglutinin (PNA) peanut Galactose -β1-3- N-acetylgalactosamine -α1-Ser / Thr
Fava Bean Lectin (VFA) Fava bean
Hemagglutinin (HA) Influenza virus
Elderberry Lectin (SNA) Black elder Neu5Ac-α2-6-GalNAc residues
Jacalin (AIL) Artocarpus integrifolia ( Sialic acid ) -Gal-β1-3-GalNAc-α1- serine / threonine
Maackia amurensis Leucoagglutinin (MAL) Asian yellow wood Neu5Ac / Gc-α2-3-Gal-β1-4-GlcNAc
Maackia amurensis hemoagglutinin (MAH) Asian yellow wood Neu5Ac / Gc-α2-3-Gal-β1-3- (Neu5Ac-α2,6) GalNac
Orange-Red Beaker Lectin (AAL) Orange-red cup Fucα1-2Galβ1-4 (Fucα1-3 / 4) Galβ1-4GlcNAc, R2-GlcNAcβ1-4 (Fucα1-6) GlcNAc-R1
Phytohemagglutinin (PHA) Legumes
Restrictocin Aspergillus restrictus mold Translational inhibition toxin
Ricin (RCA) wondertree Seed glycoprotein Translational inhibition Galactose -β1-4- N-acetylgalactosamine -β1 residues
Robin Common black locust
Snowdrop Lectin (GNA) Little snowdrop α-1-3 and α-1-6 linked mannose
Shiga toxin Shigella dysenteriae Translational inhibition Shigellosis
Soybean Lectin (SBA) Soybean
Gorse lectins (Gorse, Furze, UEA-I) Gorse UEA: Fucα1-2Gal-R
Vero toxin Enterohemorrhagic Escherichia coli Bacterial agitation
Wheat Germ Lectin (WGA) wheat GlcNAc-β1-4-GlcNAc-β1-4-GlcNAc, 5-acetyl- neuraminic acid
Sweet peas lectin (VVL) Vicia villosa

Functions and effects

Effect in nutrition

Lectins of plant origin are found in vegetables, so that the digestive tract of the human lectins is regularly exposed. Some lectins can be toxic to humans or pets in their raw state and only become irreversibly inactivated when they are cooked. Cultivated vegetables (e.g. kidney beans) with such poisonous lectins should only be consumed cooked.

The effect of lectins in the diet, according to some researchers, is to cause them to clump red blood cells. At the end of the 1990s, the naturopathic researcher Peter J. D'Adamo developed a so-called blood group diet based on his research . However, no evidence has yet been found of the supposed health benefits of this diet.

Above a certain amount, some lectins lead to headaches, vomiting, diarrhea as well as stomach and intestinal problems; in extreme cases, consumption can be fatal. In particularly lektinreichen species, such as red beans , already four or five raw seeds can cause serious symptoms in adults. Symptoms of poisoning appear quickly, usually one to three hours after consumption, and usually disappear again just as quickly - about three to four hours after onset.

Antibiotic effect

In their mode of action, lectins are often similar to antibiotics . So Ricin is a potent inhibitor of ribosomal protein biosynthesis. In some cases, lectins have a toxic effect on small organisms and are therefore used as pesticides against insects .

Messenger substances

Lectins are usually attached to the outer membrane surface . They also play a role in the communication and interaction of cells and organisms. For example, they are involved in many recognition processes. With the help of the lectin- polysaccharide interaction, bacteria such as Rhizobium trifolii can attach themselves to the roots of clover . The symbiosis of nodule bacteria and leguminous legumes is only possible with the detection and is therefore specific.

Similar recognition mechanisms play a role in the fertilization of the human egg cell .


Lectins can play a role in ontogenesis . Some plant lectins are inactivated by the germination process .


Examples of lectins are calnexin and calreticulin , which serve as chaperones in protein folding.

Sialoadhesin, a Siglec (a IgSF ) complexed with a sialic acid - glycan .
purple : glycan, green : protein-carbon, red : oxygen, blue : nitrogen, white : hydrogen


More than 500 different proteins of the IgSF - immunoglobulin - family were predicted based on bioinformatic analyzes of mammalian genomes . This includes the Siglec family ( English sialic acid-binding immunoglobulin-type lectins ), a group sialic acid binding lectins.

Found in legumes

The following table shows the lectin content of various legumes (according to the USFDA ):

variety Lectin content in hemagglutinating units (HAE)
Red kidney beans , raw 20,000-70,000
White kidney bean, raw 7,000-23,000
Broad bean , raw 1,000-7,000
Red kidney beans, well cooked 200-400

Individual evidence

  1. a b c Irwin J. Goldstein, Colleen E. Hayes: The lectins: carbohydrate-binding proteins of plants and animals. In: Advances in Carbohydrate Chemistry and Biochemistry. Volume 35, 1978, pp. 127-340. doi: 10.1016 / S0065-2318 (08) 60220-6
  2. a b c d Varki Ajit, Paul R. Crocker: I-type lectins. In: A. Varki, RD Cummings, JD Esko et al: Essentials of Glycobiology. 2nd Edition. 2009. PMID 20301278 , chapter 32
  3. a b c Patent EP1008852 : Method for the specific detection of glycosylated proteins. Registered on November 15, 1999 , published on September 3, 2003 , applicant: Aventis Behring, inventor: Annette Feussner, Jürgen Römisch.
  4. a b c Jacqueline Kupper, Cornelia Reichert: Poisoning with plants . In: Therapeutic review . tape 66 , no. 5 , 2009, p. 343-348 , doi : 10.1024 / 0040-5930.66.5.343 .
  5. a b c FDA: Bad Bug Book: Foodborne Pathogenic Microorganisms and Natural Toxins Handbook Phytohaemagglutinin. ( Memento of March 8, 2013 in the Internet Archive )
  6. Arpad Pusztai , Susan Bardocz: lectin - Biomedical Perspectives. Taylor & Francis, 2005, ISBN 0-7484-0177-6 , pp. 2ff.
  7. MT McConnell, DR Lisgarten, LJ Byrne, SC Harvey, E. Bertolo: Winter Aconite (Eranthis hyemalis) Lectin as a cytotoxic effector in the lifecycle of Caenorhabditis elegans. In: PeerJ. Volume 3, 2015, p. E1206, doi : 10.7717 / peerj.1206 , PMID 26312191 , PMC 4548470 (free full text).
  8. Leila Cusack, Emmy De Buck, Veerle Compernolle, Philippe Vandekerckhove: Blood type diets lack supporting evidence: a systematic review. In: Am J Clin Nutr. 98 (1), Jul 2013, pp. 99-104. doi: 10.3945 / ajcn.113.058693 . PMID 23697707 .
  9. ^ Information center against poisoning: kidney beans


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