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Updated: Jul 2, 2026
05:35
Surface Engineering of Pancreatic Islets with a Heparinized StarPEG Nanocoating
Published on: June 23, 2018
Suppression of insulin aggregation by heparin
Katie Giger1, Ram P Vanam, Emek Seyrek
1Department of Chemistry, Indiana University-Purdue University at Indianapolis, 402 North Blackford Street, Indianapolis, Indiana 46202, USA.
Biomacromolecules
|August 14, 2008
Summary
Heparin suppresses insulin aggregation by interfering with electrostatic interactions. This study reveals how protein charge distribution and salt concentration influence insulin
Area of Science:
- Biochemistry
- Protein aggregation
- Insulin research
Background:
- Insulin aggregation is a critical factor in diabetes and biopharmaceutical formulation.
- The role of electrostatic interactions in insulin aggregation, especially near its isoelectric point (pI), is not fully understood.
Purpose of the Study:
- To investigate the pH- and ionic strength-dependence of heparin-free insulin aggregation.
- To elucidate the mechanisms by which heparin suppresses insulin aggregation.
Main Methods:
- Turbidimetry and stopped-flow kinetics were employed to monitor insulin aggregation.
- Electrostatic modeling using DelPhi was performed to analyze protein-protein interactions.
Main Results:
- Insulin aggregation is driven by interprotein electrostatic interactions, even at the isoelectric point.
- Maximum aggregation occurred at an ionic strength of approximately 0.01 M, correlating with the Debye length and insulin dimer size.
- Heparin, a polyanion, inhibits aggregation by binding to positively charged regions of insulin, blocking interprotein interactions.
Conclusions:
- Insulin aggregation is governed by charge anisotropy and electrostatic forces, not minimized at pI.
- Heparin's inhibitory effect on insulin aggregation is attributed to its interference with these specific electrostatic interactions.
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