Detection of beta-amyloid peptide aggregation using DNA electrophoresis

DNA could readily associate with the aggregated forms of the beta-amyloid p eptides beta(1-40) and beta(25-35), giving rise to a shift in the electroph oretic mobility of DNA. As a result, DNA was retained at the top of a 1% ag arose gel. In contrast, the electrophoretic mobility of DNA was little infl uenced by the monomeric forms of beta(1-40) and beta(25-30). DNA from diffe rent sources such as lambda phage, Escherichia coli plasmid, and human gene showed similar results. However, the electrophoretic mobility of RNA was s hifted by the monomeric beta(1-40) and beta(25-35) as well as by the aggreg ated beta(1-40) and beta(25-35). The association of DNA with the aggregated beta-amyloid peptides could occur at pH 4-9. The inhibitory action of hemi n on beta-amyloid aggregation could be confirmed using the DNA mobility shi ft assay. These results indicate that the DNA mobility shift assay is usefu l for kinetic study of beta-amyloid aggregation as well as for testing of a gents that might modulate beta-amyloid aggregation. (C) 2000 Academic Press .