title: Protein-peptide interaction: study of heat-induced aggregation and gelation of β-lactoglobulin in the presence of two peptides from its own hydrolysate.
abstract: Two peptides, [f135-158] and [f135-162]-SH, were used to study the binding of the peptides to native β-lactolobulin, as well as the subsequent effects on aggregation and gelation of β-lactoglobulin. The binding of the peptide [f135-158] to β-lactoglobulin at room temperature was confirmed by SELDI-TOF-MS. It was further illustrated by increased turbidity of mixed solutions of peptide and protein (at pH 7), indicating association of proteins and peptides in larger complexes. At pH below the isoelectric point of the protein, the presence of peptides did not lead to an increased turbidity, showing the absence of complexation. The protein-peptide complexes formed at pH 7 were found to dissociate directly upon heating. After prolonged heating, extensive aggregation was observed, whereas no aggregation was seen for the pure protein or pure peptide solutions. The presence of the free sulfhydryl group in [f135-162]-SH resulted in a 10 times increase in the amount of aggregation of β-lactoglobulin upon heating, illustrating the additional effect of the free sulfhydryl group. Subsequent studies on the gel strength of heat-induced gels also showed a clear difference between these two peptides. The replacement of additional β-lactoglobulin by [f135-158] resulted in a decrease in gel strength, whereas replacement by peptide [f135-162]-SH increased gel strength.
authors.affiliation: TI Food and Nutrition, Wageningen, The Netherlands.
authors.forename: Hans A
authors.initials: HA
authors.lastname: Kosters
authors.forename: Peter A
authors.initials: PA
authors.lastname: Wierenga
authors.forename: Renko
authors.initials: R
authors.lastname: de Vries
authors.forename: Harry
authors.initials: H
authors.lastname: Gruppen
mesh_terms: D002942:Circular Dichroism; D005782:Gels / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D007782:Lactoglobulins / Q000737:chemistry* / Q000302:isolation & purification; D010455:Peptides / Q000737:chemistry*; D011485:Protein Binding; D011492:Protein Hydrolysates; D054730:Protein Interaction Domains and Motifs; D012212:Rheology; D012996:Solutions; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D013438:Sulfhydryl Compounds / Q000737:chemistry; D013696:Temperature
chemical_list: D005782:Gels; D007782:Lactoglobulins; D010455:Peptides; D011492:Protein Hydrolysates; D012996:Solutions; D013438:Sulfhydryl Compounds