Stereoselective determination of amino acids in beta-amyloid peptides and senile plaques.
A novel method for the determination of the enantiomeric composition of peptides is presented. In this paper, the focus has been on beta-amyloid peptides from deceased Alzheimer's disease patients. The peptides are hydrolyzed using mineral acid. The free amino acids are derivatized with the chiral reagent (+)- or (-)-1-(9-anthryl)-2-propyl chloroformate and subsequently separated using micellar electrokinetic chromatography (MEKC) and detected using laser-induced fluorescence (LIF) detection. The high separation efficiency of the MEKC-LIF system, yielding approximately 1 million theoretical plates/m for most amino acids, facilitates the simultaneous chiral determination of nine amino acids. The samples that have been analyzed were standard 1-40 beta-amyloid peptides, in vitro precipitated beta-amyloid fibrils, and human senile plaque samples.
Thorsén
G
G
Department of Analytical Chemistry, Stockholm University, Sweden. gunnar.thorsen@anchem.su.se
Bergquist
J
J
Westlind-Danielsson
A
A
Josefsson
B
B
D000596:Amino Acids / Q000032:analysis*; D016229:Amyloid beta-Peptides / Q000737:chemistry*; D020374:Chromatography, Micellar Electrokinetic Capillary; D006801:Humans; D006868:Hydrolysis; D066298:In Vitro Techniques; D008854:Microscopy, Electron; D010446:Peptide Fragments / Q000032:analysis*; D058225:Plaque, Amyloid / Q000737:chemistry* / Q000648:ultrastructure
D000596:Amino Acids; D016229:Amyloid beta-Peptides; D010446:Peptide Fragments