Good one indeed ... Archived Message Posted by Shyaku on October 17, 2020, 5:48 pm, in reply to "A good one from John Helmer on Navalnychock" Though I think this part is mistaken: "A leading British chemist in the field of organophosphates, reviewing the FOI’s September 15 press release, concluded: “The statement from Dr Asa Scott is pure fantasy. LC-MS/MS is a very common technique, but it cannot do the job that Dr.Scott claims. It can certainly be used to determine amino acids. However, knowing what amino acids or their ratios were measured in Navalny’s blood does not assist chemical identification. Blood concentration of amino acids is a common technique; for example, amino acids and four ratios — glutamate/citrulline, citrulline/phenylalanine, leucine plus isoleucine/phenylalanine, and arginine/phenylalanine — are an analysis performed for early diagnosis of Alzheimer’s Disease. But these ratios and the individual concentrations cannot lead to the identification of a specific chemical which has caused the change in concentration. It’s just not possible.”" It is fairly clear to me, from the redacted Swedish report, that they were looking for acetylcholinesterase adducts, i.e. Covalently-bound inhibitors, to the protein. The approach seems perfectly valid for such an assay (digest the purified protein to short peptides or amino acids under relatively gentle conditions) with the caveat that phosphoryl adducts may tend to be labile during MS/MS. Message Thread: A good one from John Helmer on Navalnychock - Tomski October 16, 2020, 3:10 pm Good one indeed ... - Shyaku October 17, 2020, 5:48 pm   Searching