The binding constant for amyloid A beta 40 peptide interaction with human serum albumin

• Published in: Biochemical and biophysical research communications Vol. 364; no. 3; pp. 714 - 718
• Main Authors: Rozga, M, Kloniecki, M, Jablonowska, A, Dadlez, M, Bal, W
• Format: Journal Article
• Language: English
• Published: 21-12-2007
• ISSN: 0006-291X
• DOI: 10.1016/j.bbrc.2007.10.080

Human serum albumin (HSA) is the major carrier of A beta peptides in blood plasma. 1:1 interaction stoichiometries were established in previous indirect antibody-based studies for both A beta 40 and A beta 42, but corresponding binding constants were not provided. In this study we applied direct titrations of HSA with A beta 40 monitored using circular dichroism spectroscopy and obtained a dissociation constant (K sub(d)) of 5+/-1 mu M for a HSA complex with A beta 40. The interaction resulted in an increase of the alpha -helical contents in the complex, compared to its components, which is quantitatively consistent with the known ability of A beta 40 to adopt a partially alpha -helical conformation in a hydrophobic environment. The relevance of these findings for the role of HSA in A beta physiology is discussed.