| Legume lectin domain | |||||||||
|---|---|---|---|---|---|---|---|---|---|
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| Identifiers | |||||||||
| Symbol | Lectin_legB | ||||||||
| Pfam | PF00139 | ||||||||
| Pfam clan | CL0004 | ||||||||
| InterPro | IPR001220 | ||||||||
| PROSITE | PDOC00278 | ||||||||
| SCOP2 | 1lem / SCOPe / SUPFAM | ||||||||
| |||||||||
Phytohaemagglutinin (PHA, or phytohemagglutinin) is a lectin found in plants, especially certain legumes. PHA actually consists of two closely related proteins, called leucoagglutinin (PHA-L) and PHA-E. These proteins cause blood cells to clump together. PHA-E cause erythrocytes (red blood cells) to clump. PHA-L causes leukocytes (white blood cells) to clump. Phytohaemagglutinin has carbohydrate-binding specificity for a complex oligosaccharide containing galactose, N-acetylglucosamine, and mannose.[2]
It is found in the highest concentrations in uncooked red kidney beans and white kidney beans (also known as cannellini),[3] and it is also found in lower quantities in many other types of green beans and other common beans (Phaseolus vulgaris), as well as broad beans (Vicia faba) such as fava beans.[4] It has a number of physiological effects and is used in medical research. In high doses, it is a toxin.[4]
The lectin has a number of effects on cell metabolism; it induces mitosis, and affects the cell membrane in regard to transport and permeability to proteins. It agglutinates most mammalian red blood cell types.[citation needed]
- ^ Hamelryck TW, Dao-Thi MH, Poortmans F, Chrispeels MJ, Wyns L, Loris R (August 1996). "The crystallographic structure of phytohemagglutinin-L". The Journal of Biological Chemistry. 271 (34): 20479–85. doi:10.1074/jbc.271.34.20479. PMID 8702788.
- ^ "PHA-E specification sheet Medicago AB: Phytohaemagglutinin" (PDF). Archived from the original (PDF) on 2012-03-04. Retrieved 2010-03-14.
- ^ "Kidney Beans". The world's healthiest foods. Archived from the original on 2007-10-18. Retrieved 2007-11-05.
- ^ a b "Bad Bug Book (2012)" (PDF). Foodborne Pathogenic Microorganisms and Natural Toxins Handbook: Phytohaemagglutinin. United States Food and Drug Administration. p. 254. Retrieved 2013-12-27.