Interaction of Chickpea (Cicer arietinum L.) Legumin with Oxidized Linoleic Acid

Abstract

Chickpea legumin has been purified and incubated under oxidizing conditions with linoleic acid to investigate the influence of this acid on the structure and nutritional quality of the protein. At the end of the incubation time, >30% of the linoleic acid was oxidized. The oxidized linoleic acid was highly detrimental to legumin, and the electrophoretic pattern of the protein was completely changed after the incubation period. Nevertheless, neither polymerization nor cleavage of the protein was observed as deduced from gel filtration chromatography, suggesting that the changes observed in native electrophoresis were probably due to oxidation of legumin. The incubation of legumin with linoleic acid also produced a diminution of the contents of methionine and histidine, by 81.3 and 24.3%, respectively. Finally, in vitro protein digestibility of chickpea legumin was also seriously affected by the incubation with linoleic acid, decreasing from 84.1 to 69.2%.

Protein–lipid interactions during the incubation of whey proteins with autoxidizing lipids

“…This is in agreement with literature data indicating that histidine seems to be the major target for reaction with lipid oxidation products (Alaiz & Giron, 1994;Sanchez-Vioque et al, 1999). Histidine seems to be easily modified as a result of exposure to 4-hydroxy-2-alkenals via a Michael-type addition of the imidazole nitrogen atom of histidine to the a,b-unsaturated bond of the 2-alkenals (Uchida & Stadtman, 1992).…”

“…Moreover, many of the lipid secondary oxidation products are difunctional by nature (for example the 4-hydroxy-2-nonenal with an electrophilic C-3 and a carbonyl group), and they can form aggregates through Michael addition at the C-3 followed by a Schiff base addition at the carbonyl group (Carini, Aldini, & Facino, 2004). Interestingly however, Sanchez-Vioque et al (1999) did not observe changes in the SDS-PAGE pattern of the legumin from chickpea incubated with linoleic acid alone. In our study however, oils were used of which the major constituents are triacylglycerols.…”

“…Therefore, a more detailed analysis of the specific molecular changes on amino acid level was performed. Changes in amino acid composition of proteins as a result of their interaction with fatty acids or secondary oxidation products have been reported (Matoba et al, 1982;Sanchez-Vioque et al, 1999;Zamora & Hidalgo, 2003). Due to their structure, tryptophan, histidine, and proline, but also lysine, cysteine, methionine, and tyrosine are reported to be mostly prone to oxidation.…”

“…A treatment with 34 mM NaBH 4 for 4 h at 37 C was performed to stabilize the proteinelipid adducts and to make them resistant to acid hydrolysis (Sanchez-Vioque et al, 1999). Further, the samples were hydrolyzed with 6 M HCl for 24 h at 110 C. For tryptophan determination alkaline hydrolysis was performed with 4.2 M NaOH for 24 h at 110 C. Hydrolysates were neutralized with NaOH or HCl to bring the pH to 2.2 and 4.25, respectively.…”

Characterisation of proteinaceous binders in artistic paintings by chromatographic techniques

“…A variety of mechanisms may play a role in the transformations occurring in the curing and ageing of proteins: the presence of other components in the paint such as lipids or cations from pigments [92,93]; the synergistic effect of particular environmental conditions such as moisture, oxidising pollutants, and UV light, leading to the formation of free radicals; and the presence of materials introduced in restoration such as organic solvents and basic reagents which favour protein hydrolysis. Based on a knowledge of protein chemistry in food sciences and in metabolic processes, possible reactions of proteinaceous media in paint layers in the course of ageing [53,88] have been suggested.…”