Is there reversible dimerization of albumin in blood plasma? And does it matter?

Autor: Harris G; Research Complex at Harwell, Rutherford Appleton Laboratory, Didcot, UK., Bradshaw ML; Department of Anaesthetics, Bradford Royal Infirmary, Bradford, UK., Halsall DJ; Department of Clinical Biochemistry, Addenbrooke's Hospital, Cambridge, UK., Scott DJ; School of Biosciences, University of Nottingham, Sutton Bonington, UK., Unwin RJ; Department of Renal Medicine, UCL Medical School, London, UK., Norden AGW; Department of Renal Medicine, UCL Medical School, London, UK.
Jazyk: angličtina
Zdroj: Experimental physiology [Exp Physiol] 2024 Oct; Vol. 109 (10), pp. 1663-1671. Date of Electronic Publication: 2024 Aug 23.
DOI: 10.1113/EP092012
Abstrakt: Most albumin in blood plasma is thought to be monomeric with some 5% covalently dimerized. However, many reports in the recent biophysics literature find that albumin is reversibly dimerized or even oligomerized. We review data on this from X-ray crystallography and diverse biophysical techniques. The number-average molecular weight of albumin would be increased by dimerization, affecting size-dependent filtration processes of albumin such as at the glycocalyx of the capillary endothelium and the podocyte slit-diaphragm of the renal glomerulus. If correct, and depending on characteristics of the process, such as K d , reversible dimerization of albumin in plasma would have major implications for normal physiology and medicine. We present quantitative models of the impact of dimerization on albumin molecular forms, on the number-average molecular weight of albumin, and estimate the effect on the colloid osmotic pressure of albumin. Dimerization reduces colloid osmotic pressure as total albumin concentration increases below that expected in the absence of dimerization. Current models of albumin filtration by the renal glomerulus would need revision to account for the dynamic size of albumin molecules filtered. More robust biophysical data are needed to give a definitive answer to the questions posed and we suggest possible approaches to this.
(© 2024 The Author(s). Experimental Physiology published by John Wiley & Sons Ltd on behalf of The Physiological Society.)
Databáze: MEDLINE
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