Peptides as standards for denaturing isoelectric focusing

✍ Scribed by Norman R. M. Watts; Dr. Rudra P. Singh

• Book ID: 102834698
• Publisher: John Wiley and Sons
• Year: 1995
• Tongue: English
• Weight: 781 KB
• Volume: 16
• Category: Article
• ISSN: 0173-0835
• DOI: 10.1002/elps.1150160106

✦ Synopsis

A set of commercially available peptides suitable for use as standards in denaturing isoelectric focusing (IEF) is described. The peptides N-procalcitonin fragment 1-57 (pl 3.98), G1n"-amyloid P-protein fragment 1-28 (pZ 5.76), gastric inhibitory polypeptide (pl 7.14), parathyroid hormone fragment 1-34 (p18.64) and human fi-endorphin (pl 9.49) can be focused to their isoelectric point in the presence of 8 M urea and 2% Nonidet P-40, and subsequently fixed and stained in polyacrylamide gels. The peptides give a linear standard curve in close agreement with a slope determined with a surface pH electrode. Under the same conditions some proteins focus to positions significantly at odds with their theoretical isoelectric point. The origins of these discrepancies and the implications for the determination of isoelectric points of unknown proteins by denaturing IEF are discussed.