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Updated: Oct 16, 2026

Absolute Quantitation of Inositol Pyrophosphates by Capillary Electrophoresis Electrospray Ionization Mass Spectrometry
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Absolute Quantitation of Inositol Pyrophosphates by Capillary Electrophoresis Electrospray Ionization Mass Spectrometry

Published on: August 13, 2021

beta-Amyloid(25-35) inhibits the activity of inositol(1,4,5)-trisphosphate-5-phosphatase

A Rönnbäck1, C J Fowler

  • 1Department of Pharmacology and Clinical Neuroscience, Umeå University, Sweden.

Amyloid : the International Journal of Experimental and Clinical Investigation : the Official Journal of the International Society of Amyloidosis
|June 8, 2000
PubMed

Insights

Beta-amyloid (A beta) peptides impact cell calcium. This study found that A beta(25-35) inhibits Ins(1,4,5)P3-5-phosphatase, affecting inositol trisphosphate metabolism but not significantly impacting calcium homeostasis.

Area of Science:

  • Neuroscience
  • Cell Biology
  • Biochemistry

Background:

  • Beta-amyloid (A beta) peptides are implicated in cellular calcium disruption.
  • Inositol 1,4,5-trisphosphate 5-phosphatase (Ins(1,4,5)P3-5-phosphatase) plays a role in calcium signaling pathways.

Purpose of the Study:

  • To investigate the effects of A beta(25-35) on the activity of soluble Ins(1,4,5)P3-5-phosphatase.
  • To determine if A beta peptides influence the metabolism of inositol trisphosphate.

Main Methods:

  • Assay of soluble rat cerebellar Ins(1,4,5)P3-5-phosphatase activity.
  • Treatment with A beta(25-35) peptide and dithiothreitol (DTT).
  • Assessment of enzyme sensitivity to glucose-6-phosphate and phytic acid.

Main Results:

  • A beta(25-35) significantly inhibited soluble Ins(1,4,5)P3-5-phosphatase activity.
  • Dithiothreitol (DTT) increased the enzyme's activity.
  • A beta(35-25) also inhibited the enzyme, but with lower potency than A beta(25-35).
  • The enzyme's sensitivity to glucose-6-phosphate and phytic acid was not significantly altered.

Conclusions:

  • A beta(25-35) affects Ins(1,4,5)P3 metabolism by inhibiting Ins(1,4,5)P3-5-phosphatase.
  • The observed inhibition potency is unlikely to be a major contributor to the broader effects of A beta peptides on calcium homeostasis.

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