Covalent modification of Alzheimer's amyloid beta-peptide in formic acid solutions.
beta-peptide is a normal component of amyloid deposits in Alzheimer's disease. In aqueous solution, beta-peptide is extremely insoluble and rapidly aggregates forming oligomeric beta-sheet structures that eventually precipitate from solution. Presumably, this process is related to the production of amyloid deposits in Alzheimer's disease. Formic acid is commonly used to dissolve the beta-peptides and prevent aggregation in biological and biophysical studies. However, a side-reaction which covalently modifies beta-peptide is encountered with formic acid. In this report, fast atom bombardment mass spectrometry and tandem mass spectrometry demonstrate that both Ser8 and Ser26 become O-formylated in 70% aqueous formic acid solutions. The implications of this O-formylation upon the aggregational properties of beta-peptide are discussed.
Orlando
R
R
Suntory Institute for Bioorganic Research, Osaka, Japan.
Kenny
P T
PT
Zagorski
M G
MG
D000595:Amino Acid Sequence; D016229:Amyloid beta-Peptides / Q000138:chemical synthesis / Q000737:chemistry*; D005561:Formates; D013058:Mass Spectrometry; D008969:Molecular Sequence Data; D011487:Protein Conformation; D012996:Solutions; D016339:Spectrometry, Mass, Fast Atom Bombardment
D016229:Amyloid beta-Peptides; D005561:Formates; D012996:Solutions; C030544:formic acid