Gamma-Amanitin

Gamma-Amanitin is a cyclic peptide and one of the Amanitins, a group of toxins found in several species of the Amanita genus of mushrooms. It is a highly toxic substance and a potent inhibitor of RNA polymerase II, a vital enzyme involved in the synthesis of messenger RNA (mRNA), micro RNA, and small nuclear RNA (snRNA).

Structure and Properties

Gamma-Amanitin has a complex structure consisting of eight amino acids arranged in a large macrocycle. The molecule also contains a tryptathionine bridge, a unique feature among the amanitins. This structure is responsible for its high stability and resistance to degradation by enzymes.

Toxicity

Gamma-Amanitin is highly toxic to humans and animals. It works by binding to the RNA polymerase II enzyme, effectively halting the synthesis of mRNA. This prevents the production of proteins, leading to cell death. Symptoms of gamma-amanitin poisoning include severe abdominal pain, vomiting, and diarrhea, which can lead to dehydration and kidney failure. In severe cases, it can cause liver damage, leading to death.

Treatment

There is currently no specific antidote for gamma-amanitin poisoning. Treatment is mainly supportive, focusing on maintaining hydration and treating symptoms. Some experimental treatments have shown promise, including the use of Silibinin, a compound found in milk thistle, which appears to inhibit the uptake of amanitins into liver cells.

Occurrence

Gamma-Amanitin is found in several species of the Amanita genus, including Amanita phalloides, commonly known as the death cap, and Amanita virosa, known as the destroying angel. These mushrooms are highly poisonous and are responsible for the majority of fatal mushroom poisonings worldwide.

See Also

• Alpha-Amanitin
• Beta-Amanitin
• Amanita phalloides
• Amanita virosa

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