Characterization of bovine serum albumin glycated with glucose, galactose and lactose.

Abstract

The non-enzymatic reaction between reducing sugars and proteins, known as glycation, has received increased attention from nutritional and medical research. In addition, there is a large interest in obtaining glycoconjugates of pure well-characterized oligosaccharides for biological research. In this study, glycation of bovine serum albumin (BSA) by d-glucose, d-galactose and d-lactose under dry-heat at 60 degrees C for 30, 60, 120, 180 or 240 min was assessed and the glycated products studied in order to establish their biological recognition by lectins. BSA glycation was monitored using gel electrophoresis, determination of available amino groups and lectin binding assays. The BSA molecular mass increase and glycation sites were investigated by mass spectrometry and through digestion with trypsin and chymotrypsin. Depending on time and type of sugar, differences in BSA conjugation were achieved. Modified BSA revealed reduction of amino groups' availability and slower migration through SDS/PAGE. d-galactose was more reactive than d-glucose or d-lactose, leading to the coupling of 10, 3 and 1 sugar residues, respectively, after 120 minutes of reaction. BSA lysines (K) were the preferred modified amino acids; both K256 and K420 appeared the most available for conjugation. Only BSA-lactose showed biological recognition by specific lectins.

Differentiation of glycated residue numbers on heat‐induced structural changes of bovine serum albumin

“…13 When BSA was heated with Gal at 60 ∘ C for 120 min, seven glycated Lys residues (Lys-93, 116, 232, 261, 322, 350 and 396) were identified. 12 Glycated Lys residues (Lys-132 and Lys-136) are next to fluorophore Trp-134 in domain IB. Glycated Arg residue (Arg-217) is close to fluorophore Trp-213 in domain IIA.…”

In vitro and in vivo inhibition of maillard reaction products using amino acids, modified proteins, vitamins, and genistein: A review

“…Different sugar exhibit different reactivities. For example, pentose sugars (e.g., ribose) are more reactive than hexoses (e.g., glucose) due to their greater electrophilicity (Chevalier, Chobert, Genot, & Haertlé, ; Chevalier, Chobert, Popineau, Nicolas, & Haertlé, ; Laroque et al, ; Ledesma‐Osuna, Amos‐Clamont, & Vazquez‐Moreno, ). However, among hexoses, galactose is more reactive than glucose due to a higher steady state concentration of the reactive open chain form of galacotse than glucose (Cui, ).…”

Bacterial recognition of thermal glycation products derived from porcine serum albumin with lactose.

“…Except for monosaccharides, the conjugation of carbohydrates to protein makes them susceptible to biological recognition by plant lectins (Blome & Schengrund, 2008;Ledesma-Osuna et al, 2008). ELLA assays were used to confirm that galactose residues were available from the produced neoglycans.…”

“…The early stage chemistry of non-enzymatic protein glycation involves an initial nucleophilic substitution reaction between sugar carbonyl groups and amino groups of proteins to form a Schiff´s base that undergoes spontaneous changes known as the Amadori rearrangement (Singh et al, 2001). Controlled and limited glycation at this point enables a direct attachment to protein without any prior modification or chemical activation of the reagents (Ledesma-Osuna et al, 2008). Sarabia-Sainz et al (2009) and Ledesma-Osuna et al (2008) demonstrated that lactosylated porcine serum albumin (PSA) neoglycans obtained by Maillard reaction interact with galactose-specific K88 adhesin.…”

“…Controlled and limited glycation at this point enables a direct attachment to protein without any prior modification or chemical activation of the reagents (Ledesma-Osuna et al, 2008). Sarabia-Sainz et al (2009) and Ledesma-Osuna et al (2008) demonstrated that lactosylated porcine serum albumin (PSA) neoglycans obtained by Maillard reaction interact with galactose-specific K88 adhesin. This microbial lectin expressed on the Escherichia coli K88 cell surface is responsible for the initial infection of piglets that results in diarrhea.…”