The degradation of Aβ 25–35 by the serine protease plasmin is inhibited by aluminium

Abstract

The catabolism of amyloid beta peptides (Aβ) may be important in their accumulation in the brain in both early and late-onset Alzheimer's disease (AD). The serine protease plasmin is one of a suite of proteases implicated in AD. It is a promoter of α-cleavage of the amyloid β precursor protein (AβPP) and will degrade Aβ in vitro. Herein we have demonstrated cleavage of the amyloidogenic Aβ_25–35 by plasmin to produce the non-amyloidogenic fragment Aβ_25–35. The activity of plasmin was halved by pre-mixing it with aluminium (Al) prior to its addition to the peptide. An interaction between Al and proteases involved in the catabolism of Aβ might define the putative link between Al and AD.