Toxins, Amanita

Note Like sulfuric acid (q.v.) ort/io-phosphoric add is a universal reagent, with which almost all classes of substance can be detected at high temperatures (150-180 °C) by charring e.g. high molecular weight hydrocarbons (mineral oils) [20]. The colors and fluorescences produced at lower temperatures (<120°C) and their intensities are very dependent on the temperature and period of heating. It is not possible to use meta- or pyrophosphoric acid in place of or/Ao-phosphoric add, since, for instance, amanita toxins react well with alcoholic phosphoric add only weakly with aqueous phosphoric add and not at all with meta- or pyrophosphoric acid [17]. 

The chemical synthesis of the Amanita toxins has presented several problems, in particular those related to the formation of the sulfur bridge. The latter has been explored with model compounds.[2 31 It has been found that the synthesis of the (sulfanyl)indole moiety can be achieved by reacting an indole compound with an alkanesulfenyl chloride. A model tryptathionine compound has been prepared by reacting A-acyl-L-cysteine and /V-acyl-L-tryptophan in the presence of A-chlorosuccinimide in glacial acetic acid at room temperature.[4] The sulfanylation reaction has been subsequently exploited for the selective chemical modification of tryptophan residues in proteins using 2-nitrophenylsulfenyl chlorideJ5 ... 

N-Methylmorpholine [1, 690]. In the mixed anhydride synthesis of peptides, N-methylmorpholine was found to give little or no racemization in cases where triethylamine, the commonly used base, caused extensive racemization.1 Trimethyl-amine, a potent racemizer, can be used successfully if an excess is avoided. N-Methylmorpholine was used by Wieland2 in the synthesis of antamanide, a cyclic decapeptide of Amanita phalloides, which counteracts the lethal action of Amanita toxins. 

Block, S.S. etal. 1955. Ths. Amanita toxins in mushrooms Journal of Agricultural and Food Chemistry 3 584. 

T er, VE. etal. 1966. Occurrence o Amanita toxins in American collections of d 3.dhf Amanitas Journal ofPharmaceu-tical Sciences 53(6) 590-593. 

Ibotenic acid a-amino-3-hydroxy-5-isoxazole-acetic acid, M, 158, m.p. 145 C (d.), a psychotropic, weakly insecticidal substance. I. a. and its decarboxylation product, Muscimol (see), are amanita toxins. I. a. is found only in a few species of Amanita (fly agaric), at concentrations averaging 0.05 % of the fresh weight. It is pharmacologically very active, but less so than muscimol in most tests. Another La. derivative is Tricholomic acid (see). 

The most important compounds of this group of fungi toxins are the cyclic peptides amatoxins or amanita toxins (10-202) and phaUo-toxins (10-203) of the death cap (Amanita phalloides, Amanitaceae) that cause the phaUoidin poisoning. The main toxin is phaUoidin... 

Amanita toxins (amataxkis) are cyclic octapeptides that reduce protein synthesis by inhibiting ribonucleic acid (RN polymerase and transcription. 

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