Print Email Facebook Twitter Detection of a soluble form of BACE-1 in human cerebrospinal fluid by a sensitive activity assay Title Detection of a soluble form of BACE-1 in human cerebrospinal fluid by a sensitive activity assay Author TNO Kwaliteit van Leven Verheijen, J.H. Huisman, L.G.M. van Lent, N. Neumann, U. Paganetti, P. Erik Hack, C. Bouwman, F. Lindeman, J. Bollen, E.L.E.M. Hanemaaijer, R. Publication year 2006 Abstract Background: Formation of deposits of the insoluble amyloid β-peptide is believed to be causally related with neurodegeneration in Alzheimer disease (AD). The β-peptide originates from a larger amyloid precursor protein (APP) by the action of proteolytic enzymes. The first proteolytic event leading to amyloid formation is the cleavage of APP by the membrane-bound aspartyl protease BACE-1, also known as memapsin-2. Inhibition of BACE-1 is thought to be a therapeutic approach to AD. Measuring BACE-1 activity in biological samples would be useful to elucidate the mechanism of AD and for development of AD drugs. Methods: We developed a sensitive and specific activity assay for BACE-1. The assay is based on a genetically engineered proenzyme that is specifically activated by BACE-1. The resulting active enzyme is measured with a chromogenic substrate. The use of 2 coupled reactions produces a detection limit as low as 0.4 pmol/L. Results: The assay detected BACE-1 activity in extracts of human brain tissue as well as, unexpectedly, in human cerebrospinal fluid (CSF). Gel electrophoresis and Western blotting identified the BACE-1 present in CSF as a truncated soluble form of the originally membrane-bound BACE-1. Conclusion: Detection of the soluble form of BACE-1 in CSF, a relatively easily accessible biological fluid, may be useful for monitoring the effects of drug candidates in vivo and may have diagnostic or prognostic applications. © 2006 American Association for Clinical Chemistry. Chemicals / CAS: amyloid beta protein, 109770-29-8; aspartic proteinase, 78169-47-8; cathepsin D, 9025-26-7; renin, 61506-93-2, 9015-94-5; Amyloid Precursor Protein Secretases, EC 3.4.-; Aspartic Endopeptidases, EC 3.4.23.-; BACE1 protein, human, EC 18.104.22.168; CASP3 protein, human, EC 3.4.22.-; Caspase 3, EC 3.4.22.-; Caspases, EC 3.4.22.-; Endopeptidases, EC 3.4.-; Protein Precursors; Tissue Extracts Subject Biomedical Researchamyloid beta proteinamyloid precursor proteinaspartic proteinasebeta amyloid converting enzyme 1beta secretasecathepsin Dcathepsin Echromogenic substrateenzyme precursorreninunclassified drugAlzheimer diseasebody fluidbrain tissuecerebrospinal fluid analysisdiagnostic valueenzyme activationenzyme assaygel electrophoresisgenetic engineeringhuman tissuemonitoringnerve degenerationprognosisprotein cerebrospinal fluid levelprotein degradationsensitivity and specificityWestern blottingAmyloid Precursor Protein SecretasesAspartic EndopeptidasesBrainCaspase 3CaspasesCross ReactionsEndopeptidasesHumansImmunoassayProtein PrecursorsSensitivity and SpecificitySolubilityTissue Extracts To reference this document use: http://resolver.tudelft.nl/uuid:2b9184c2-cd6e-4cd0-9071-76fb47e195d7 DOI https://doi.org/10.1373/clinchem.2006.066720 TNO identifier 239287 ISSN 0009-9147 Source Clinical Chemistry, 52 (52), 1168-1174 Document type article Files To receive the publication files, please send an e-mail request to TNO Library.