ELECTROPHORETIC SEPARATION OF BETA-A4 PEPTIDE-(1-40) AND PEPTIDE-(1-42)

Different sodium dodecyl sulfate-polyacrylamide gel electrophoresis (S DS-PAGE) systems designed for the separation of peptides were compared for their usefulness in separating synthetic beta-amyloid peptides be ta A4 (1-40) and beta A4 (1-42). Clear resolution was achieved by addi tion of 8 M urea to the separation gel and use of a multiphasic buffer system employing bicine and sulfate as trailing and leading ions, res pectively (bicine/Tris/urea gels). Under these conditions, the longer peptide migrated faster than the one ending at amino acid 40. The usef ulness of this SDS-PAGE system for the analysis of beta A4-related pep tides generated during cellular metabolism was demonstrated by immunop recipitation and electrophoretic separation of radiolabeled peptides s ecreted by cells transfected with amyloid precursor protein cDNAs. (C) 1996 Academic Press, Inc.