HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) All Versions of this Article: clinchem.2006.066720v1 52/6/1168    most recent Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Web of Science (6) Citing Articles via Google Scholar Google Scholar Articles by Verheijen, J. H. Articles by Hanemaaijer, R. Search for Related Content PubMed PubMed Citation Articles by Verheijen, J. H. Articles by Hanemaaijer, R. Related Collections General Clinical Chemistry

Detection of a Soluble Form of BACE-1 in Human Cerebrospinal Fluid by a Sensitive Activity Assay

¹ TNO Quality of Life, Biomedical Research, Leiden, The Netherlands.⁴ Departments of Vascular Surgery and⁵ Neurology, Leiden University Medical Center, Leiden, The Netherlands.
² Novartis Institutes for BioMedical Research, Neuroscience Discovery, Novartis Pharma AG, Basel, Switzerland.
³ Department of Clinical Chemistry, VU Medical Center, Amsterdam, The Netherlands.

^aAddress correspondence to this author at: TNO Quality of Life, Biomedical Research, PO Box 2215, 2300 CE Leiden, The Netherlands. Fax 31-71-5181904; e-mail JH.Verheijen{at}pg.tno.nl.

Background: Formation of deposits of the insoluble amyloid ß-peptide is believed to be causally related with neurodegeneration in Alzheimer disease (AD). The ß-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.

The following articles in journals at HighWire Press have cited this article:

				D. R. Taylor, E. T. Parkin, S. L. Cocklin, J. R. Ault, A. E. Ashcroft, A. J. Turner, and N. M. Hooper Role of ADAMs in the Ectodomain Shedding and Conformational Conversion of the Prion Protein J. Biol. Chem., August 21, 2009; 284(34): 22590 - 22600. [Abstract] [Full Text] [PDF]

				H. Zetterberg, U. Andreasson, O. Hansson, G. Wu, S. Sankaranarayanan, M. E. Andersson, P. Buchhave, E. Londos, R. M. Umek, L. Minthon, et al. Elevated Cerebrospinal Fluid BACE1 Activity in Incipient Alzheimer Disease Arch Neurol, August 1, 2008; 65(8): 1102 - 1107. [Abstract] [Full Text] [PDF]

				Z. Zhong, M. Ewers, S. Teipel, K. Burger, A. Wallin, K. Blennow, P. He, C. McAllister, H. Hampel, and Y. Shen Levels of beta-Secretase (BACE1) in Cerebrospinal Fluid as a Predictor of Risk in Mild Cognitive Impairment Arch Gen Psychiatry, June 1, 2007; 64(6): 718 - 726. [Abstract] [Full Text] [PDF]