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Homogeneous Time-resolved Förster Resonance Energy Transfer-based Assay for Detection of Insulin Secretion
Published on: May 10, 2018
Interaction of IAPP and insulin with model interfaces studied using neutron reflectometry
Christoph Jeworrek1, Oliver Hollmann, Roland Steitz
1Fakultät Chemie, Technische Universität Dortmund, D-44221 Dortmund, Germany.
Biophysical Journal
|February 3, 2009
Summary
Islet amyloid polypeptide (IAPP) strongly adsorbs to hydrophobic surfaces, unlike insulin. This difference in adsorption behavior at charged interfaces may influence IAPP and insulin fibril formation.
Area of Science:
- Biophysics
- Biochemistry
- Materials Science
Background:
- Islet amyloid polypeptide (IAPP) and insulin are produced in pancreatic beta-cells and can interact with lipid membranes.
- Both peptides are prone to forming amyloid fibrils, a process implicated in diseases like type 2 diabetes.
Purpose of the Study:
- To investigate the adsorption behavior of IAPP and insulin at different water-polymer interfaces.
- To differentiate the roles of hydrophobic and electrostatic interactions in peptide adsorption.
- To understand how interfacial properties influence amyloid fibril formation.
Main Methods:
- Utilized neutron reflectometry to determine peptide adsorption profiles.
- Employed three distinct water-polymer model interfaces (hydrophobic and hydrophilic/charged).
- Varied ionic strength (100 mM NaCl) to assess electrostatic effects.
Main Results:
- IAPP showed strongest adsorption to a hydrophobic poly-(styrene) surface.
- Adsorption of IAPP to a negatively charged poly-(styrene sulfonate) interface decreased by 50% and was negligible at 100 mM NaCl.
- Insulin, despite its negative charge, strongly adsorbed to the hydrophilic, negatively charged interface.
Conclusions:
- IAPP exhibits a strong affinity for hydrophobic surfaces.
- Electrostatic repulsion and ionic strength limit IAPP adsorption to negatively charged hydrophilic surfaces.
- Insulin's accumulation at negatively charged hydrophilic interfaces may promote initial fibril formation.
