The interplay between copper(II), human serum albumin, fatty acids, and carbonylating agent interferes with Cys 34 thiol reactivity and copper binding
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Cys34 thiol group of human serum albumin (HSA) represents major plasma antioxidant. Its reactivity is influenced by multiple factors. The influence of fatty acids (FA; saturated, mono, and poly unsaturated acids from fish oil) binding to HSA, on copper(II) binding affinity and Cys34 thiol group accessibility/reactivity, in the presence of carbonylation agent (methylglyoxal, MG) was examined. HSA–copper(II) content, thiol group reactivity, and HSA carbonylation level were monitored spectrophotometrically. Changes in HSA were followed by fluorescence spectroscopy and native PAG electrophoresis. FA/HSA molar ratio was screened by GC. Together, binding of copper(II) ions and FA to HSA increase the reactivity of Cys34 thiol group (depending on the type of FA), with constant contribution of copper(II) ions of one-third. Carbonylation of FA–HSA–Cu(II) complexes caused a decrease in the Cys34 thiol group content, accompanied by a decrease in the content of HSA-bound copper. The carbonylation level of guanidine groups was not affected by FAs and copper(II) binding. Fluorescent emission spectra of FA–HSA–Cu(II)–MG complexes showed conformational changes in HSA molecule. Although binding of fatty acids and copper ions caused a significant increase in the thiol group reactivity, Cys34 thiol from FA–HSA–Cu(II) complexes reacted with MG in smaller extent than expected, probably as a consequence of conformational changes introduced by carbonylation. Increase in the percentage of reacted-free thiol groups with MG (due to FA and copper binding) may not seem to be very significant, but it is very important in complex biological systems, where catalytic metal is present.
KeywordsHuman serum albumin Copper(II) Fatty acids Carbonylation HSA Cys34 thiol group reactivity
Fish oil fatty acids
Human serum albumin
- Def HSA
Complex HSA with FA and copper(II) ion
Cys34 free thiol group of HSA
HSA modified with MG
This work was supported by The Ministry of Education, Science and Technological Development of Serbia with Grant no. 172049. The authors acknowledge support of the FP7 RegPot Project FCUB ERA GA no. 256716.
- 2.Peters T Jr (1995) All about albumin: biochemistry, genetics, and medical applications, 1st edn. Academic, New YorkGoogle Scholar
- 28.Burgeiro A, Fuhrmann A, Cherian S, Espinoza D, Jarak I, Carvalho RA, Loureiro M, Patrício M, Antunes M, Carvalho E (2016) Glucose uptake and lipid metabolism are impaired in epicardial adipose tissue from heart failure patients with or without diabetes. Am J Physiol Endocrinol Metab 310(7):E550–E564CrossRefGoogle Scholar
- 34.Gryzunov YA, Arroyo A, Vigne J-L, Zhao Q, Tyurin VA, Hubel CA, Gandley RE, Vladimirov YA, Taylor RN, Kagan VE (2003) Binding of fatty acids facilitates oxidation of cysteine-34 and converts copper–albumin complexes from antioxidants to prooxidants. Arch Biochem Biophys 413:53–66CrossRefGoogle Scholar
- 41.Blache D, Bourdon E, Salloignon P, Lucchi G, Ducoroy P, Petit J-M, Verges B, Lagrost L (2015) Glycated albumin with loss of fatty acid binding capacity contributes to enhanced arachidonate oxygenation and platelet hyperactivity: relevance in patients with type 2 diabetes. Diabetes 64(3):960–972CrossRefGoogle Scholar