Phytohaemagglutinin
Phytohaemagglutinin (PHA) is a lectin derived from the seeds of the garden bean (Phaseolus vulgaris). It occurs in the form of tetramers composed of two related polypeptides (PHA-L and PHA-E). The markings L and E correspond to leukoagglutination and erythroagglutination abilities of PHA subunits. [1] PHA is used, for example, as a mitogen to stimulate the division of lymphocytes in cytogenetic examinations or to activate latent HIV-1 in peripheral blood lymphocytes.
In high doses, PHA has toxic effects. It is found in the raw or uncooked seeds of a number of legumes. Measured in hemagglutination units (hau), the concentration in raw red beans can be as high as 70 000 hau, while in cooked beans it is only 200-400 hau. Heating the beans to less than 80 °C can increase the toxicity by up to five times, making them much more toxic than when raw. PHA poisoning manifests itself 1 to 3 hours after ingestion nausea and vomitingm. [2]
Links[edit | edit source]
Related Articles[edit | edit source]
References[edit | edit source]
- ↑ HAMELRYCK, Thomas W. , et al. The Crystallographic Structure of Phytohemagglutinin-L. Journal of Biological Chemistry [online]. 1996, vol. 271, no. 34, p. 20479–20485, Available from <http://www.jbc.org/content/271/34/20479.full>. ISSN 0021-9258 (Print), 1083-351X (On-line). PMID: 8702788.
- ↑ FDA. Bad Bug Book : BBB – Phytohaemagglutinin [online]. ©2009. [cit. 2010-06-29]. <https://www.fda.gov/food/foodsafety/foodborneillness/foodborneillnessfoodbornepathogensnaturaltoxins/badbugbook/ucm071092.htm>.
