Peptide-based toxins

Mushroom-Aman/fa pf7a//o/des Amanitins - peptide-based toxins 200... 

Other Peptide Toxin Producing Cyanobacteria. No other cyanobacteria genera have been analyzed for the presence of toxic peptides. Based on toxicity signs however it is thought that peptide toxins are present in certain isolates of Anabaena flos-aquae (J) and Oscillatorla agardhil (9,17). 

The first edition of Food Analysis by HPLC fulfilled a need because no other book was available on all major topics of food compounds for the food analyst or engineer. In this second edition, completely revised chapters on amino acids, peptides, proteins, lipids, carbohydrates, vitamins, organic acids, organic bases, toxins, additives, antibacterials, pesticide residues, brewery products, nitrosamines, and anions and cations contain the most recent information on sample cleanup, derivatization, separation, and detection. New chapters have been added on alcohols, phenolic compounds, pigments, and residues of growth promoters. 

Proteins can also be dangerous or unhealthy. For many who suffer from allergies to agents like pollen, it is proteins on the surface of the pollen that cause an immune response that triggers the allergic reaction. More seriously, many natural toxins are proteins. Snake venom is one example of a naturally occurring protein-based toxin, see also Active Site Amino Acid Denaturation Enzymes Fibrous Proteins Globular Proteins Neurotransmitters Peptide Bond Protein Solubility Protein Synthesis Protein Translation RNA Synthesis Secondary Structure Tertiary Structure Transmembrane Proteins Venom. 

DRE Suffield is also investigating the use of CE and CE-Laser Induced Fluorescence (LIF) Detection for ultra-high sensitive analysis under field laboratory conditions. Some specific applications for highly polar, water soluble molecules, such as proteins, peptides and toxins, have been developed. DRE Suffield, in cooperation with the University of Alberta, is also developing miniaturized, silica-chip based CE instrumentation and field portable CE-LIF instruments for detection and identification of biological and chemical warfare agents. 

In general, nonconventional protein foods must be competitive with conventional plant and animal protein sources on the bases of cost delivered to the consumer, nutritional value to humans or animals, functional value in foods, sensory quality, and social and cultural acceptability. Also, requirements of regulatory agencies in different countries for freedom from toxins or toxic residues in single-cell protein products, toxic glycosides in leaf protein products, pathogenic microorganisms, heavy metals and toxins in fish protein concentrates, or inhibitory or toxic peptide components in synthetic peptides must be met before new nonconventional food or feed protein products can be marketed. 

Cyproase 1 is in effect a new enzyme, produced by systematic protein engineering firmly based on sound chemical principles. Its status as an enzyme mimic may be debatable its efficiency is not. It was shown to hydrolyze 25% of bonds to proline in a (denatured) peptide toxin in two hours at pH 70, with some 400 turnovers. It is one of the two most efficient enzyme mimics we will encounter in this article1131... 

It is interesting to note that the first demonstration of tyrosinate fluorescence in a protein was made by Szabo et al.au> with two cytotoxins from the Indian cobra Naja naja. While exhibiting different relative amounts of the two emission bands, both toxins had fluorescence at 304 and 345 nm, with the 304-nm band being greatly reduced on excitation at 290 nm. Since these proteins have three tyrosine residues and no tryptophan, it was concluded that the 345-nm emission band was due to tyrosinate. Furthermore, tyrosinate appeared to be formed in the excited state from a hydrogen-bonded ground-state complex based on the absorption spectra. Szabo subsequently reexamined these peptide samples and found that they were contaminated with tryptophan (A. G. Szabo, personal communication). While Szabo s approach to the demonstration of tyrosinate fluorescence was correct based on his initial data, his subsequent finding exemplifies an important caution if tyrosinate emission is suspected, every effort must be made to demonstrate the... 

Cholera toxin This protein catalyzes the covalent insertion of an ADP-ribosyl moiety derived from NAD into an unidentified site of tubulin, based on SDS—gel electrophoresis and peptide fragmentation patterns (Hawkins and Browning, 1982). Because only about 0.1% of the tubulin dimers appear to become modified, the association with microtubule control remains tenuous... 

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