Immunocapture-based fluorometric assay for the measurement of insulin-degrading enzyme activity in brain tissue homogenates

Research output: Contribution to journalArticle (Academic Journal)

23 Citations (Scopus)

Abstract

Internally quenched fluorogenic substrates are commonly used for measuring enzyme activity in biological samples and allow high sensitivity and continuous real-time measurement that is well suited for high throughput analysis. We describe the development and optimisation of an immunocapture-based assay that uses the fluorogenic peptide substrate (Mca-RPPGFSAFK(Dnp)) and allows the specific measurement of insulin-degrading enzyme (IDE) activity in brain tissue homogenates. This fluorogenic substrate can be cleaved by a number of enzymes including neprilysin (NEP), endothelin-converting enzyme-1 (ECE-1) and angiotensin-converting enzyme (ACE), as well as IDE, and we have previously shown that discrimination between these individual enzymes is not readily achieved in tissue homogenates, even in the presence of selective inhibitors and pH conditions. We tested a panel of IDE antibodies to isolate and capture IDE from brain tissue homogenates and found that immunocapture with antibody to the inactive domain of IDE prior to the addition of fluorogenic substrate allows sensitive (linear at 156-2500ng/ml) and specific measurement of IDE activity and negligible cross-reactivity with NEP, ACE or ECE-1. This assay should allow the measurement of IDE enzyme levels in a variety of biological tissues and may be useful in study of diseases such as Alzheimer's disease and insulin-dependent diabetes.
Translated title of the contributionImmunocapture-based fluorometric assay for the measurement of insulin-degrading enzyme activity in brain tissue homogenates
Original languageEnglish
Pages (from-to)177 - 181
Number of pages5
JournalJournal of Neuroscience Methods
Volume169 (1)
DOIs
Publication statusPublished - Mar 2008

Bibliographical note

Publisher: Elsevier

Fingerprint Dive into the research topics of 'Immunocapture-based fluorometric assay for the measurement of insulin-degrading enzyme activity in brain tissue homogenates'. Together they form a unique fingerprint.

  • Cite this