Regulation of amyloid β-peptide levels by enzymatic degradation

It is generally accepted that amyloid beta peptides (A beta) play a significant role in the etiology of Alzheimer's disease. The A beta peptides are produced by the sequential cleavage of an amyloid precursor protein by a beta secretase followed by cleavage by a gamma secretase. The clearance of A beta appears to be due primarily by the action of one or more peptidases. An imbalance between the rate of synthesis and the rate of clearance of A beta is now considered a possible contributor to the onset of Alzheimer's disease. This review focuses on peptidases that have been proposed to contribute to A beta catabolism and discusses the evidence for their participation in A beta peptide clearance in vivo.