ABSTRACT
α-Dicarbonyl compounds (α-DCs), such as glyoxal, methylglyoxal and 2,3-butanedione, are highly reactive substances occurring in thermally treated and fermented foods, that may react with amino and sulphydryl groups of side chains of proteins to form Maillard reaction end products, inducing a negative impact on the digestibility and on nutritional value of protein. In recent years the role of food derived α-DCs in gastroduodenal tract is under investigation to understand whether excess consumption of such dietary compounds might be a risk for human health. In this study the interactions between a mixture of glyoxal, methylglyoxal and 2,3-butanedione and the digestive enzymes (pepsin and pancreatin) were studied. The results showed that during gastroduodenal digestion α-DCs react with digestive enzymes to produce carbonylated proteins. Moreover, undigested and digested α-DC cytotoxicity against human cells, as well as their ability to inhibit the function of human enzymes responsible for DNA repair were shown.
Subject(s)
Diacetyl/toxicity , Digestion , Glyoxal/toxicity , Pancreatin/metabolism , Pepsin A/antagonists & inhibitors , Pepsin A/metabolism , Pyruvaldehyde/toxicity , Cell Line , Cell Survival/drug effects , DNA Polymerase beta/antagonists & inhibitors , DNA Polymerase beta/metabolism , Humans , Models, Biological , Pancreatin/antagonists & inhibitors , Protein Carbonylation/drug effectsABSTRACT
An automated docking procedure was applied on a series of 26 reversible and competitive indole inhibitors of human pancreatic phospholipase A2 (hp-PLA2). X-ray data of this enzyme are not available and the structure was then reconstructed exploiting its protein sequence and the crystallographic data of a bovine pancreatic source. The docking data were used to build a three-dimensional quantitative structure-activity relationship (3D QSAR) model, established using the comparative molecular field analysis (CoMFA) method. This model, joined to the previous one developed for the indole inhibitors of human non-pancreatic secretory phospholipase A2 (hnps-PLA2), an enzyme involved in inflammation processes, will allow for the selection of new strong anti-inflammatory drugs with negligible side effects, at least at the level of hp-PLA2.
Subject(s)
Enzyme Inhibitors/chemistry , Indoles/chemistry , Models, Molecular , Pancreas/enzymology , Pancreatin/antagonists & inhibitors , Phospholipases A/antagonists & inhibitors , Animals , Anti-Inflammatory Agents/pharmacology , Cattle , Computer Simulation , Crystallization , Enzyme Inhibitors/pharmacology , Humans , Indoles/pharmacology , Molecular Conformation , Phospholipases A2 , Reproducibility of Results , Structure-Activity Relationship , SwineABSTRACT
A method for immobilizing pancreation on carboxymethylcellulose (CMC) is proposed. The optimum reaction conditions were determined: CMC, 1 x 10(-4) M; 1-ethyl 3-(dimethylaminopropyl)-carbodiimide, 2 x 10(-4) M; incubation time, 18 h at 4 degrees C. They allow obtaining a conjugate of the enzyme with the polymer displaying 85% of the protease and 92% of the esterase activity. Both the native and immobilized enzymes were shown to contain thermolabile and thermostable fractions with different inactivation constants. Immobilization of the enzyme was found to increase its thermal stability by a factor of 1.5 to 3. Thermodynamic constants of blood protein hydrolysis by native and immobilized enzymes were determined.
