Toxin proteins, biological

Stability of the BoNT protein should be considered in an assessment of the threat posed by intentional release of the toxins. In addition to the remarkable persistence of the toxin in biological fluids and beverages described above, BoNT remains a potent environmental threat. BoNT/A was subjected to desiccation to simulate the residue of an intentional release. Following 28 days of drying, the toxin still possessed remarkable paralytic properties (Williams et ah, 2007). 

It is obvious from the provisional risk assessment values for microcystins, and, being of the same order of magnitude of mammalian toxicity, similar values may be calculated for the cyanobacterial neurotoxins, that sensitive detection methods are required to detect these low concentrations of toxins. Of the biological methods of detection discussed earlier, the mouse and invertebrate bioassays are not sensitive enough without concentration of water samples, in that they are only able to detect mg of microcystins per litre. Only the immunoassays (ng-/rg 1 and the protein phosphatase inhibition assays (ng O... 

The clinical significance of protein-based impurities relates to (a) their potential biological activities and (b) their antigenicity. Whereas some contaminants may display no undesirable biological activity, others may exhibit activities deleterious to either the product itself (e.g. proteases that could modify/degrade the product) or the recipient patient (e.g. the presence of contaminating toxins). 

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