SELDI-TOF-MS as a rapid tool to study food related protein–peptide interactions

The use of SELDI-TOF-MS was investigated as a rapid tool to detect peptides present in a crude protein hydrolysate, which are capable to bind to intact food proteins. A purified and well characterized ß-lactoglobulin preparation was extensively hydrolyzed by the Glu-specific enzyme V8 from Staphylococcus aureus. Characterization of this hydrolysate by SELDI-TOF-MS and MALDI-TOF-MS resulted in sixteen identified peptides, which covered 98% of the primary sequence of ß-lactoglobulin. To identify peptides capable to bind non-covalently to intact proteins, the complete hydrolysate was applied to covalently bound ovalbumin, glycinin, ß-lactoglobulin and ß-casein on a SELDI ProteinChip PS-20. Six peptides (AB [f29–45], AB [f90–108], AB [f138–158], B [f63–89], AB [f1–45], AB [f135–162] bound to these four different proteins with decreasing affinity to glycinin > ovalbumin > ß-lactoglobulin > ß-casein. Peptides, which bound to these proteins were AB [f1–45] and AB [f135–158]. Using different concentrations of Triton X-100 (up to 2%) as a washing step prior to MS detection, enabled a rapid distinction between the peptides bound with respect to protein binding capacity.