Alzheimer's disease amyloid beta peptides in vitro electrochemical oxidation

作者：Enache Teodor Adrian; Oliveira Brett Ana Maria^*

来源：Bioelectrochemistry, 2017, 114: 13-23.

DOI：10.1016/j.bioelechem.2016.11.003

• Amyloid beta peptide oxidation
• Alzheimer's disease
• Electroactive amino acids
• Voltammetry
• Adsorption
• Glassy carbon electrode

The oxidative behaviour of the human amyloid beta (A beta(1-40) and A beta(1-42)) peptides and a group of similar peptides: control inverse (A beta(40-1) and A beta(42-1)), mutants (A beta(1-40)Phe(10) and A beta(1-40)Nle(35)), rat A beta(1-40)Rat, and fragments (A beta(1-28),A beta(1-16), A beta(10-20), A beta(12-28), and A beta(17-42)), in solution or adsorbed, at a glassy carbon electrode, by cyclic and differential pulse voltammetry, were investigated and compared. Structurally the A beta(1-40) and A beta(1-42) sequences contain five electroactive amino add residues, one tyrosine (Tyr(10)), three histidines (His(6), His(13) and His(14)) and one methionine (Met(35)). The A beta peptide 3D structure influenced the exposure of the redox residues to the electrode surface and their oxidation peak currents. Depending on the amino acid sequence length and content, the A beta peptides gave one or two oxidation peaks. The first electron transfer reaction corresponded to the tyrosine amino add residue oxidation, and the second to both histidines and methionine amino acid residues. The highest contribution to the second oxidation peak current was from His(13), followed by His(14) and His(6) residues, and Met(35) residue had the lowest contribution. The A beta peptides electron transfer depended on peptide hydrophobicity and 3D structure, the redox residues position in the sequence, the redox residues close to N-termini giving the highest oxidation peak currents.

• 出版日期2017-4