title: Fatty acids binding to human serum albumin: Changes of reactivity and glycation level of Cysteine-34 free thiol group with methylglyoxal.
abstract: Fatty acids (FAs) binding to human serum albumin (HSA) could lead to the changes of Cys-34 thiol group accessibility and reactivity, i.e. its scavenger capacity and antioxidant property. The influence of saturated, mono and poly unsaturated, and fish oil FAs binding to HSA on the carbonylation level and the reactivity of HSA-SH and HSA modified with methylglyoxal (MG-HSA-SH) was investigated. Changes of thiol group reactivity were followed by determination of pseudo first order rate constant (k') for thiols reaction with 5,5'-dithiobis(2-nitrobenzoic acid). HSA changes were monitored using native PAG electrophoresis and fluorescence spectroscopy. For FA/HSA molar ratios screening, qTLC and GC were used. FAs increase thiol group carbonylation levels from 8% to 20%. The k' values obtained for FAs-free HSA-SH and FAs-free MG-HSA-SH are almost equal (7.5×10(-3) and 7.7×10(-3)s(-1), resp.). Binding of all FAs amplify the reactivity (k' values from 14.6×10(-3) to 26.0×10(-3)s(-1)) of HSA-SH group for 2-3.5times in the order: palmitic, docosahexaenoic, fish oil extract, stearic, oleic, myristic and eicosapentaenoic acid, due to HSA conformational changes. FAs-bound MG-HSA-SH samples follow that pattern, but their k' values (from 9.8×10(-3) to 14.3×10(-3)s(-1)) were lower compared to unmodified HSA due to additional conformation changes of HSA molecules during carbonylation. Carbonylation level and reactivity of Cys34 thiol group of unmodified and carbonylated HSA depend on type of FAs bound to HSA, which implies the possibility for modulation of -SH reactivity (scavenger capacity and antioxidant property) by FAs as a supplement.
authors.affiliation: Department of Biochemistry, Faculty of Chemistry, University of Belgrade, Studentski trg 12-16, Belgrade 11158, Serbia.
authors.forename: Ivan D
authors.initials: ID
authors.lastname: Pavićević
authors.affiliation: Department of Biochemistry, Faculty of Chemistry, University of Belgrade, Studentski trg 12-16, Belgrade 11158, Serbia.
authors.forename: Vesna B
authors.initials: VB
authors.lastname: Jovanović
authors.affiliation: Institute for Medical Research, Laboratory for Nutrition and Metabolism, University of Belgrade, Belgrade, Serbia.
authors.forename: Marija M
authors.initials: MM
authors.lastname: Takić
authors.affiliation: Department of Biochemistry, Faculty of Chemistry, University of Belgrade, Studentski trg 12-16, Belgrade 11158, Serbia.
authors.forename: Ana Z
authors.initials: AZ
authors.lastname: Penezić
authors.affiliation: Department of Biochemistry, Faculty of Chemistry, University of Belgrade, Studentski trg 12-16, Belgrade 11158, Serbia.
authors.forename: Jelena M
authors.initials: JM
authors.lastname: Aćimović
authors.affiliation: Department of Biochemistry, Faculty of Chemistry, University of Belgrade, Studentski trg 12-16, Belgrade 11158, Serbia. Electronic address: ljmandic@chem.bg.ac.rs.
authors.forename: Ljuba M
authors.initials: LM
authors.lastname: Mandić
mesh_terms: D003545:Cysteine / Q000032:analysis / Q000737:chemistry*; D005227:Fatty Acids / Q000737:chemistry*; D005395:Fish Oils / Q000378:metabolism; D016166:Free Radical Scavengers / Q000737:chemistry; D006031:Glycosylation; D006801:Humans; D007700:Kinetics; D011485:Protein Binding; D011765:Pyruvaldehyde / Q000737:chemistry*; D012709:Serum Albumin / Q000737:chemistry*
chemical_list: D005227:Fatty Acids; D005395:Fish Oils; D016166:Free Radical Scavengers; D012709:Serum Albumin; D011765:Pyruvaldehyde; D003545:Cysteine
keywords: Albumin; Fatty acids binding; Methylglyoxal; Protein carbonylation; Thiol group reactivity