Biochemistry of the amatoxins: preparation and characterization of a stably iodinated α-amanitin

Morris, Paul W.; Venton, D. L.; Kelley, Kathleen M.

doi:10.1021/bi00597a021

Cited by 18 publications

(28 citation statements)

References 31 publications

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“…1 and Table 1). The only known pK a -value for these compound classes in the literature is 9.72 for a-amanitin [19] which is very similar to the pK a of phenol (9.89 [20]). Therefore, we attempted to separate the toxins investigated in alkaline separation buffer in which they should be (partly) dissociated.…”

Section: Separationmentioning

confidence: 99%

Identification of toxic oligopeptides in Amanita fungi employing capillary electrophoresis‐electrospray ionization‐mass spectrometry with positive and negative ion detection

2008

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The identification of toxic oligopeptides employing CE-ESI-MS is presented. The analytes studied ama- and phallotoxins are of significant forensic interest because over 90% of the lethal cases of fungus poisoning in man are caused by species of Amanita which contain these toxins. A CE method was developed to separate the toxins alpha-, beta- and gamma-amanitin, phalloidin and phallacidin. Their fragmentation patterns in MS(n) experiments were investigated in the positive and in the negative ion mode, also the influence of the sheath liquid mixture of the used interface on the S/N. Method validation included the determination of the LOD and the repeatability of the migration time and peak area for both detection modes. With the optimized method LODs of 13-79 ng/mL (17-87 nmol/L) were reached. The CE-MS procedure was successfully applied to the identification of ama- and phallotoxins in extracts of air-dried mushroom samples.

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Section: Separationmentioning

confidence: 99%

Identification of toxic oligopeptides in Amanita fungi employing capillary electrophoresis‐electrospray ionization‐mass spectrometry with positive and negative ion detection

2008

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“…Iodination of a-amanitin occurs in 7'position, and the use of '''I is a further possibility for introducing radioactivity (107). Tritium was introduced into 0-amanitin by hydrogenation of the 6'4 1 -phenyl)tetrazolyl ether.…”

Section: Chemical Modifications Of Amatoxinsmentioning

confidence: 99%

The toxic peptides from Amanita mushrooms

Wieland

1983

International Journal of Peptide and Protein Research

143

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The results of 50 years of effort in the chemistry of Amanita toxins are reviewed. The phallotoxins, fast acting components, but not responsible for fatal intoxications after ingestion, are bicyclic heptapeptides. They combine with F-actin, stabilizing this protein against several destabilizing influences. The virotoxins likewise fast acting are monocyclic heptapeptides. The amatoxins which are the real toxins lead to death within several days by inhibiting the enzymatic synthesis of m-RNA. They are bicyclic octapeptides. The' structures of all of these compounds are described, as well as conformations, chemical reactions and modifications, syntheses and correlations between structures and biological activities.

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“…To the best of our knowledge, α-amanitin has never been chemically synthesized, which thwarts this route to producing α-amanitin labeled with either radioactive or stable isotopes. Chemical radiolabeling with 125 I led to a chemically distinct compound with reduced activity (Morris et al., 1978; Faulstich et al, 1981). In vivo labeling is hindered by the difficulty of culturing most species of Amanita .…”

Section: Introductionmentioning

confidence: 99%

Production of 15N-labeled α-amanitin in Galerina marginata

Luo

DuBois

Sgambelluri

et al. 2015

Toxicon

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α-Amanitin is the major causal constituent of deadly Amanita mushrooms that account for the majority of fatal mushroom poisonings worldwide. It is also an important biochemical tool for the study of its target, RNA polymerase II. The commercial supply of this bicyclic peptide comes directly from A. phalloides, the death cap mushroom, which is collected from its natural habitat. Isotopically labeled amanitin could be useful for clinical and forensic applications, but α-amanitin has not been chemically synthesized and A. phalloides cannot be cultured on artificial medium. Using Galerina marginata, an unrelated saprobic mushroom that grows and produces α-amanitin in culture, we describe a method for producing 15N-labeled α-amanitin using growth media containing 15N as sole nitrogen source. A key to success was preparing 15N-enriched yeast extract via a novel method designated “glass bead-assisted maturation.” In the presence of the labeled yeast extract and 15N-NH4Cl, α-amanitin was produced with >97% isotope enrichment. The labeled product was confirmed by HPLC, high-resolution mass spectrometry, and NMR.

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Biochemistry of the amatoxins: preparation and characterization of a stably iodinated α-amanitin

Cited by 18 publications

References 31 publications

Identification of toxic oligopeptides in Amanita fungi employing capillary electrophoresis‐electrospray ionization‐mass spectrometry with positive and negative ion detection

Identification of toxic oligopeptides in Amanita fungi employing capillary electrophoresis‐electrospray ionization‐mass spectrometry with positive and negative ion detection

The toxic peptides from Amanita mushrooms

Production of 15N-labeled α-amanitin in Galerina marginata

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