Endogenous Proteins Controlling Amyloid β-Peptide Polymerization
We report that certain plasma proteins, at physiological concentrations, are potent inhibitors of amyloid β-peptide (Aβ) polymerization. These proteins are also present in cerebrospinal fluid, but at low concentrations having little or no effect on Aβ. Thirteen proteins representing more than 90%...
Gespeichert in:
Veröffentlicht in: | The Journal of biological chemistry 1999-06, Vol.274 (23), p.15990 |
---|---|
Hauptverfasser: | , , , , , , , , , |
Format: | Artikel |
Sprache: | eng |
Online-Zugang: | Volltext |
Tags: |
Tag hinzufügen
Keine Tags, Fügen Sie den ersten Tag hinzu!
|
Zusammenfassung: | We report that certain plasma proteins, at physiological concentrations, are potent inhibitors of amyloid β-peptide (Aβ) polymerization.
These proteins are also present in cerebrospinal fluid, but at low concentrations having little or no effect on Aβ. Thirteen
proteins representing more than 90% of the protein content in plasma and cerebrospinal fluid were studied. Quantitatively,
albumin was the most important protein, representing 60% of the total amyloid inhibitory activity, followed by α 1 -antitrypsin and immunoglobulins A and G. Albumin suppressed amyloid formation by binding to the oligomeric or polymeric Aβ,
blocking a further addition of peptide. This effect was also observed when the incorporation of labeled Aβ into genuine β-amyloid
in tissue section was studied. The Aβ and the anti-diabetic drug tolbutamide apparently bind to the same site on albumin.
Tolbutamide displaces Aβ from albumin, increasing its free concentration and enhancing amyloid formation. The present results
suggest that several endogenous proteins are negative regulators of amyloid formation. Plasma contains at least 300 times
more amyloid inhibitory activity than cerebrospinal fluid. These findings may provide one explanation as to why β-amyloid
deposits are not found in peripheral tissues but are only found in the central nervous system. Moreover, the data suggest
that some drugs that display an affinity for albumin may enhance β-amyloid formation and promote the development of Alzheimerâs
disease. |
---|---|
ISSN: | 0021-9258 1083-351X |
DOI: | 10.1074/jbc.274.23.15990 |