Isoelectric focusing of peptides

✍ Scribed by Pier Giorgio Righetti; Francesco Chillemi

• Book ID: 104144034
• Publisher: Elsevier Science
• Year: 1978
• Tongue: English
• Weight: 963 KB
• Volume: 157
• Category: Article
• ISSN: 1873-3778
• DOI: 10.1016/s0021-9673(00)92339-2

✦ Synopsis

Analytical isoelectri& focusing of peptides in 0.7~mm thick gel slabs, in presence of 8 M urea, is made possible by staining the gel directly in Coomassie Brilliant Blue G-250 dissolved in 1 N H2S0,12% trichloroacetic acid solution. The carrier ampholytes are soluble in this solvent whereas the peptides form a macromolecular aggregate with the dye, thus being trapped and precipitated within the gel matrix_ The minimum critical peptide length for precipitation and staining is of the order of 15 amino acids. Below this length, only some basic, lysine-containing peptides are able to form faint, stained precipitates. About 20 pg peptide per an average band contained in a 3.5mm3 gel volume can be detected by this technique. It is hypothesized that the dye crosslinks different peptide chains by binding to basic residues via its SO,-groups.