RESUMO
The aggregation behavior of the major component of Alzheimer's disease-related, amyloid peptides, Abeta-(1-40) and Abeta-(1-42), was studied in solution using dynamic light scattering. With most solvents employed, we found fibrils coexisting with oligomeric Abeta species. Pronounced differences were observed in aggregation of Abeta-(1-40) and (1-42) sequences in acetonitrile-water mixtures. Cofactors such as Zn2+ were found to induce deaggregation of Abeta instead of aggregation. The results indicated that the initial state of the peptide immediately after synthesis is rather poorly defined. Using freezing instead of lyophilization after the final peptide synthesis step, may partially relieve these problems.
Assuntos
Doença de Alzheimer/metabolismo , Peptídeos beta-Amiloides/química , Espalhamento de Radiação , Proteína Amiloide A Sérica/química , Acetonitrilas/química , Dimetil Sulfóxido/química , Humanos , Luz , Biossíntese Peptídica , Propanóis/química , Fatores de Tempo , Trifluoretanol/química , Zinco/químicaRESUMO
To identify the role of the block of glutamic acid residues characteristic for the gastrin molecule, a series of shortened peptides related to the human little-gastrin-I sequence were synthesized. The biological activities of these gastrin peptides strongly suggest in the pentaglutamic acid sequence a specific information for a pronounced amplification of the hormonal activity.