Fig 5.
The subtle difference in the Aβ peptide composition of the soluble pool of brain Aβ is revealed by acid-urea polyacrylamide gels. The Aβ peptide composition of the carbonate-soluble hippocampal extracts from 12-month-old PDAPP+/+, clusterin+/+ and PDAPP+/+, clusterin−/− mice was determined by acid-urea gel analysis (n = 4 per group). Human Aβ40 and Aβ42 synthetic peptides are used for mass and migration comparisons. Soluble extracts analyzed under the completely denaturing conditions demonstrate that human Aβ42 is the predominant Aβ peptide present. Human Aβ40 was readily detectable in extracts from all PDAPP+/+, clusterin+/+ mice examined, whereas human Aβ40 could not be detected in PDAPP+/+, clusterin−/− extracts.