Modification of Bovine β-Lactoglobulin by Glycation in a Powdered State or in an Aqueous Solution:  Effect on Association Behavior and Protein Conformation

Abstract

The effect of glycation with lactose on the association behavior and conformational state of bovine beta-lactoglobulin (beta-LG) was studied, using size exclusion chromatography, polyacrylamide gel electrophoresis, proteolytic susceptibility, and binding of a fluorescent probe. Two modification treatments were used, i.e., aqueous solution glycation and dry-way glycation. The results showed that the latter treatment did not significantly alter the nativelike behavior of the protein while the former treatment led to important structural changes. These changes resulted in a specific denatured beta-LG monomer, which covalently associated via the free thiol group. The homodimers thus formed and the expanded monomers underwent subsequent aggregation into a high molecular weight species, via noncovalent interactions. The association behavior of glycated beta-LG is discussed with respect to the known multistep denaturation/aggregation process of nonmodified beta-LG.

Glycation improves the thermostability of trypsin and chymotrypsin

“…There is evidence that limited glycation increases the thermostability of proteins (Liang and Rossi, 1990;Marshall and Rabinowitz, 1976;Morgan et al, 1999;Yeboah et al, 2004). In the case of trypsin (Kato et al, 1993), limited glycation carried out over 4 days was reported to increase the thermostability as measured by DSC; however, the increase as measured by retention of activity after incubation at elevated temperatures (60-708C) was modest and measured for only a 1 min incubation.…”

Functional and molecular properties of calcium precipitated soy glycinin and the effect of glycation with κ-carrageenan

“…Improvement in functionality of soy proteins has also been achieved through hydrolysis and chemical modification (Achouri, Zhang, & Shiying, 1998;Qi, Hettiarachy, & Kalapathy, 1997;Wagner, Sorgentini, & Anon, 1996). It is also known that the Maillard reaction (glycation), carried out under dry state and well controlled conditions (temperature, relative humidity and time), is an adequate method for improving functionality of protein (Achouri, Boye, Yaylayan, & Yeboah, 2005;Chevalier, Chobert, Popineau, Nicolas, & Haertlé, 2001;Chobert, Gaudin, Dalgalarrondo, & Haertlé, 2006;Morgan, Leonil, Molle, & Bouhallab, 1999a).…”

Lactose crystallisation and early Maillard reaction in skim milk powder and whey protein concentrates

“…Numerous published results have shown that EMR can progress with a very high rate in a powdered matrix with intermediate a w (0.3-0.7). Model studies on the solid-state EMR between the main whey protein, β-lactoglobulin (β-LG) and lactose have shown that the rate of Maillard reaction is accelerated at intermediate water activity and have provided a very extensive characterisation of glycoconjugates [13][14][15]. These studies demonstrated that extensively lactosylated β-LG -obtained after a dry heating (50 °C) of powder under a relative humidity of 65% -was more structurally stable than β-LG reacted with lactose in an aqueous solution.…”