HPLC chromatogram of tryptic digest of the amyloid subunit protein. The trypsin digestion product was dissolved in 50% acetic acid and fractionated on an Ultrasphere ODS column (0.46 × 25 cm) equilibrated with 0.1% TFA in water and eluted with a 0% to 60% acetonitrile linear gradient in 120 minutes. The labeled peaks yielded the sequences in Fig 1. Multiple peaks containing the T2 sequence may be the result of changes in hydrophobicity due to cis-trans isomerization of Pro residues.