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Cell-free Biochemical Fluorometric Enzymatic Assay for High-throughput Measurement of Lipid Peroxidation in High Density Lipoprotein
Published on: October 12, 2017
The lipocalin alpha1-microglobulin has radical scavenging activity
Bo Akerström1, Ghassan J Maghzal, Christine C Winterbourn
1Department of Clinical Sciences, Lund University, 22184 Lund, Sweden. bo.akerstrom@med.lu.se
The Journal of Biological Chemistry
|September 4, 2007
Summary
Alpha-1-microglobulin (alpha(1)m) acts as a reductant and scavenger of organic radicals. This lipocalin reduces ABTS radicals and covalently binds them, suggesting a protective role in vivo.
Area of Science:
- Biochemistry
- Proteomics
- Free Radical Chemistry
Background:
- Alpha-1-microglobulin (alpha(1)m) is a plasma glycoprotein with known reductase properties.
- Previous studies suggest alpha(1)m binds and scavenges heme and tryptophan metabolites.
Purpose of the Study:
- To investigate the role of alpha(1)m as a reductant of organic radicals.
- To study the interaction between alpha(1)m and the ABTS radical.
Main Methods:
- Studied the reaction kinetics of alpha(1)m with ABTS radical.
- Utilized liquid chromatography/mass spectrometry to identify reaction products.
Main Results:
- Alpha-1-microglobulin (alpha(1)m) readily reduced ABTS radical with a rate constant of 6.3 x 10^3 M^-1 s^-1.
- A second product formed via covalent attachment of ABTS radical to alpha(1)m tyrosine residues.
- Both reactions were dependent on the cysteine residue at position 34 of alpha(1)m.
Conclusions:
- Alpha-1-microglobulin (alpha(1)m) sequentially reduces and then covalently traps ABTS radicals.
- These findings support a potential in vivo role for alpha(1)m as a radical reductant and scavenger.
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