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Updated: Jan 6, 2026

A Rapid and Specific Microplate Assay for the Determination of Intra- and Extracellular Ascorbate in Cultured Cells
Published on: April 11, 2014
Influence of Ascorbic Acid on the Structure and Function of Alpha-2- macroglobulin: Investigations using
Syed Saqib Ali1, Mohammad Khalid Zia1, Tooba Siddiqui1
1Department of Biochemistry, Faculty of Life Sciences, Aligarh Muslim University, Aligarh-202002, India.
Background:
Ascorbic acid is a classic dietary antioxidant which plays an important role in the body of human beings. It is commonly found in various foods as well as taken as dietary supplement.
Objective:
The plasma ascorbic acid concentration may range from low, as in chronic or acute oxidative stress to high if delivered intravenously during cancer treatment. Sheep alpha-2- macroglobulin (α2M), a human α2M homologue is a large tetrameric glycoprotein of 630 kDa with antiproteinase activity, found in sheep's blood.
Methods:
In the present study, the interaction of ascorbic acid with alpha-2-macroglobulin was explored in the presence of visible light by utilizing various spectroscopic techniques and isothermal titration calorimetry (ITC).
Results:
UV-vis and fluorescence spectroscopy suggests the formation of a complex between ascorbic acid and α2M apparent by increased absorbance and decreased fluorescence. Secondary structural changes in the α2M were investigated by CD and FT-IR spectroscopy. Our findings suggest the induction of subtle conformational changes in α2M induced by ascorbic acid. Thermodynamics signatures of ascorbic acid and α2M interaction indicate that the binding is an enthalpy-driven process.
Conclusion:
It is possible that ascorbic acid binds and compromises antiproteinase activity of α2M by inducing changes in the secondary structure of the protein.
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