Body peptide identification

Schmerr and Jenny established a CE-based immunoassay for the detection of prion protein (24). In this competitive assay, peptides derived from the prion protein and labeled with fluorescein were used. This allowed them to distinguish scrapie-infected brain preparations from noninfected. For identification, the ratio between the peaks resulting from the free and the com-plexed peptide with a specific antibody was used. The results were in agreement with other data on the brain preparations achieved by Western blot analysis. The CE-based assay provides the advantage of direct detection of the scrapie protein in blood and tissue preparations with high sensitivity. Furthermore, due to the small sample amount needed for analysis, the CE-based assay is applicable to the putative diagnostics of prion protein in body fluids. 

Detection of snake toxins and toxin antibodies in body fluids remains very important for the identification of the biting species and the correct management of envenomation. As snake venoms consist of a complex mixture of pharmacologically active peptides and proteins, detection is usually approached by immimological techniques. Radioimmimoassay (RIA) using specific monoclonal antibodies has proved to be highly reliable and sensitive. However, the difficulty of handling radioisotopes and the need of elaborate equipment limit its application in... 

Another approach to imaging dosed compounds involves using MS scans alone (14, 15). This was demonstrated for both an injected P-peptide (15) and a small molecule with its metabolites (14) in whole-body rats and mice. The advantage to this approach is mostly speed of acquisition, as all signals obtained in the full mass range can be imaged in one experiment. However, it lacks the unambiguous identification of compounds that is typically obtained from an MS/MS experiment. 

Gonzalez-Guerrero PR, Rigual R, Gonzalez C. Opioid peptides in the rabbit carotid body identification and evidence for co-utilization and interactions with dopamine. JNeurochem 1993 60 1762-1768. 

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