ABSTRACT
Few studies exist on the influence of processing methods on structural changes and allergenic potential of hazelnut proteins. This study focused on the effect of glycation (Maillard reaction) on the immunoreactivity and degranulation capacity of the purified hazelnut 7S globulin, Cor a 11. After heating, the extent of the Maillard reaction, sensitivity to proteolysis, binding of human IgE or rabbit IgG, and degranulation capacity were analyzed. Changes in electrophoretic mobility, amount of free amino groups, and contents of bound sugar and fructosamine indicated that glycation of Cor a 11 occurred at all conditions. Glycation at 37 °C did not influence the specific IgG or IgE binding and was decreased after heating at 60 and 145 °C. Heating, with or without glucose, at 145 °C increased basophil degranulation capacity. The results suggest that glycation of Cor a 11 at 60 and 145 °C may decrease the IgE/IgG binding properties but not the degranulation capacity of basophils. This is possibly related to aggregation of the proteins as a result of the Maillard reaction.
Subject(s)
Allergens/chemistry , Allergens/immunology , Corylus/chemistry , Maillard Reaction , Plant Proteins/chemistry , Plant Proteins/immunology , Animals , Basophil Degranulation Test , Corylus/immunology , Glycosylation , Hot Temperature , Humans , Immunoglobulin E/metabolism , Immunoglobulin G/metabolism , Nut Hypersensitivity/immunology , Rabbits , Structure-Activity RelationshipABSTRACT
Milk is the source of beta-casomorphins--biologically active peptides with opioid activity--which are suspected to play various roles in the human body. The local influence of exogenous opioid peptides on gastrointestinal functions has been widely reported. After passing the gut barrier, beta-casomorphins may affect the functions of immunological system, as well as dopaminergic, serotoninergic and GABA-ergic systems in brain, regulate the opioid receptor development and elicit behavioral effects. However, possibilities and mechanisms of the intestinal transport of beta-casomorphins in human body in vivo have not been reported so far. In our research, the transepithelial transport of micro-opioid receptor agonists--human beta-casomorphin-5 and 7(BCM5, BCM7) and antagonist--lactoferroxin A (LCF A) have been investigated using Caco-2 monolayer. In order to determine the pathway of investigated peptide transport across Caco-2 monolayer, two directions of the transport (apical to basolateral and basolateral to apical) have been studied. All investigated peptides were transported across the human intestinal cell line Caco-2 and the curves of cumulative amount of transported peptides in time were linear in each case. In addition, the hydrolysis of beta-casomorphins during 60 min of experiment by dipeptidyl peptidase IV was observed. The data suggest the possibility of transport of opioid peptides derived from food across human intestinal mucosa.
Subject(s)
Endorphins/metabolism , Lactoferrin/metabolism , Peptide Fragments/metabolism , Receptors, Opioid, mu/agonists , Receptors, Opioid, mu/antagonists & inhibitors , Biological Transport , Caco-2 Cells , Cell Membrane Permeability/drug effects , Endocytosis/drug effects , Endocytosis/physiology , Epithelium/metabolism , Humans , Intestinal Mucosa/metabolism , Oligopeptides/metabolismABSTRACT
Milk is the best, complete food important for the development and nourishment of a neonate. Except for nutrients, milk contains biologically active opioid peptides derived from beta-casein, named beta-casomorphins (BCMs), which can exert effects in the gastrointestinal tract as well as in the whole body of neonates. The content of beta-casomorphins in human milk during maturation phases has not been studied so far. The aim of this study was to determine the content of beta-casomorphin-5 and -7 in human milk in different phases of lactation. A significantly higher concentration of both beta-casomorphins was found in colostrum than in mature milk. The concentration of beta-casomorphin in milk collected in the second month of lactation was similar to the level obtained in the fourth month of lactation. The content of beta-casomorphins in human milk was observed with the period of lactation. The level of opioid peptides may depend on the function of these peptides in neonate's body and may be associated with the maturation process.
Subject(s)
Endorphins/analysis , Lactation , Milk, Human/chemistry , Animals , Chromatography, High Pressure Liquid , Female , Male , Spectrophotometry, UltravioletABSTRACT
Beta-casomorphins, opioid peptides present in mother's milk, are a good substrate for DPPIV (EC 3.4.14.5) which is a major factor limiting the half-life of biologically active peptides. Serum DPPIV activity of two groups of infants (healthy and atopic dermatitis) and contents of beta-casomorphin-5 and -7 in their mothers' milk were determined in the study. We have found correlation between those two parameters in the group of children with atopic dermatitis syndromes, while no such a correlation was found in the control group.
