Cytotoxic and Allergenic Potential of Bioactive Proteins and Peptides

Abstract

This review article deals with the assessment of cytotoxic and allergenic potential of bioactive proteins and peptides. It is evident that 'novel' foods or nutraceuticals containing bioactive proteins and peptides must fulfill their proposed "health claim". Furthermore, there is a need to assess their potential to exert adverse effects before they can be made widely available to consumers. A brief overview of compounds (i.e. proteins and peptides of animal and plant origin) and mechanisms involved in cytotoxic and allergenic (adverse) reactions is given along with some recent results obtained from ongoing studies. There are numerous proteins and peptides of plant and animal origin that are known to exhibit cytotoxic effects. There is evidence that many cytotoxic compounds described in the literature exclusively affect malignant cells leading to the assumption that a cancer protective effect could exist for such bioactive proteins and peptides. All the constituents that are responsible for the allergenicity of foods (as well as of pollens) are proteinaceous in nature. Some protein breakdown products, i.e. peptide fragments, may conserve part of the allergenicity of the native protein and thus can also be considered as allergens. The molecular basis of IgE recognition underlying cow's milk protein allergy is described. Some results from studies on volunteers fed caseinophosphopeptides or potentially hypotensive milk protein hydrolysates illustrate the major difference between allergenicity and immunogenicity. The data presented on the relationship between the structure of food proteins and peptides and their allergenicity shows the difficulty in trying to assess the "non-allergenicity" of products derived from an allergenic source, even if the process used involved extensive hydrolysis of the native protein(s). A 'weight of evidence approach' for assessing the potential allergenicity of a novel protein with no history of prior allergenicity is also presented with regard to the current EU Regulations.

Influence of buffer type and concentration on the peptide composition of trypsin hydrolysates of β-lactoglobulin

“…It is intended to determine points in the hydrolysis process when certain peptide precursors are further cleaved and eliminated (for example those peptides implicated in epitopic reactions and cytotoxicity (Hartmann, Wal, Bernard, & Pentzien, 2007)). In addition, it is intended to determine a time to stop the reaction just when particular peptides of interest having specific functionalities are released in order to prevent further cleavage and loss.…”

Hydrolysis of β-lactoglobulin by trypsin under acidic pH and analysis of the hydrolysates with MALDI–TOF–MS/MS

“…In that regard, even where matrix-assisted laser desorption/ionisation time-of-flight tandem mass spectrometry (MALDI-TOF-MS/MS) has been used, a single matrix, usually a-cyano-4-hydroxycinnamic acid (HCCA), was used to monitor small peptides (<4 kDa) with the rest being ignored, a likely under-estimation of the hydrolysis process. Furthermore, some peptides posses undesirable side-effects (Hartmann, Wal, Bernard, & Pentzien, 2007) and avoidance of their production is desirable.…”

Using Fluorous Amino Acids to Modulate the Biological Activity of an Antimicrobial Peptide

“…For example, membrane-active peptides are known to be important in membrane fusion and ion-channel formation, and have also been found to have anticancer and antiviral activities. [29][30][31][32] …”