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Proteins are one of the primary components of the food, both in terms of nutrition and function. They are main source of amino acids, essential for synthesis of proteins, and also source of energy. Additionally, many proteins exhibit specific biological activities, which may have effect on functional or pro-health properties of food products. These proteins and their hydrolysis products, peptides, may influence the properties of food and human organism. The number of commercially available food products containing bioactive peptides is very low, apart from that milk proteins are their rich source. It could be supposed that number of available products with declared activity will rise in near future because of observed strong uptrend on interest in such products. Molecular and biological properties of milk proteins, as precursors of bioactive peptides was characterised in the work. Therefore, the strategy of research and obtaining of such peptides both in laboralory and industrial scale, as well as the range of their commercial application, was presented. Several examples of research efforts presenting high potential to develop new products containing bioactive peptides from milk proteins and predetermined as nutraceuticals was described.
Oceniono wpływ dodatku flawomycyny, Bactocellu i Bio-Mos-u na wartość rzeźną tusz, skład chemiczny mięsa oraz udział SFA, MUFA i PUFA we frakcji lipidowej m. longissimus dorsi. Wyniki badań wskazują na możliwość efektywnego zastąpienia antybiotyku paszowego dodatkami naturalnymi.
Analizie bioinformatycznej poddano 89 peptydów immunoaktywnych dostępnych w bazie BIOPEP. Obecność fragmentów potencjalnie immunoaktywnych stwierdzono w 90 ze 150 sekwencji analizowanych białek. Sekwencje aminokwasowe badanych peptydów analizowano z uwzględnieniem: długości łańcucha, udziału procentowego poszczególnych aminokwasów, pI, molowego współczynnika ekstynkcji, indeksu hydropatii i ładunku wypadkowego. Ponadto określono możliwości ich uwalniania in silico przez enzymy proteolityczne. Na podstawie komputerowej analizy z zastosowaniem programu ProtParam stwierdzono, że immunoaktywne peptydy to głównie fragmenty hydrofilowe, w sekwencji których przeważają takie aminokwasy, jak: Lys, Arg i Pro, obdarzone ładunkiem dodatnim w neutralnym pH. W komputerowej symulacji proteolizy in silico wybranych 11 białek żywności o największej częstości występowania peptydów immunoaktywnych (parametr A > 0,02) wykazano, że tylko trzy enzymy: chymaza (EC 3.4.21.39), elastaza trzustkowa (EC 3.4.21.36) i endopeptydaza glicylowa (EC 3.4.22.25), spośród dostępnych w bazie BIOPEP, wykazywały specyficzność pozwalającą na uwalnianie peptydów immunoaktywnych w układzie jednego enzymu. Produktami hydrolizy analizowanych białek, przy użyciu wybranych enzymów proteolitycznych, były głównie 2 - 3 aminokwasowe fragmenty peptydowe.
Milk proteins, a source of bioactive peptides, are the subject of numerous research studies aiming to, among others, evaluate their properties as precursors of biologi-cally active peptides. Physiologically active peptides released from their precursors may interact with selected receptors and affect the overall condition and health of humans. By relying on the BIOPEP database of proteins and bioactive peptides, developed by the Department of Food Biochemistry at the University of Warmia and Mazury in Olsztyn (www.uwm.edu.pl/biochemia), the profiles of potential activity of milk proteins were determined and the function of those proteins as bioactive peptide precursors was evaluated based on a quantitative criterion, i.e. the occurrence frequency of bioactive fragments (A). The study revealed that milk proteins are mainly a source of peptides with the following types of activity: antihypertensive (Amax = 0.225), immunomodulating (0.024), smooth muscle contracting (0.011), antioxidative (0.029), dipeptidyl peptidase IV inhibitors (0.148), opioid (0.073), opioid antagonistic (0.053), bonding and transporting metals and metal ions (0.024), antibacterial and antiviral (0.024), and antithrombotic (0.029). The enzymes capable of releasing bioactive peptides from precursor proteins were determined for every type of activity. The results of the experiment indicate that milk proteins such as lactoferrin, α-lactalbumin, β-casein and κ-casein hydrolysed by trypsin can be a relatively abundant source of biologically active peptides.
A structural analysis was conducted of peptides responsible for inducing celiac disease, as well as of the structural fragments they are located in, i.e. the so-called “extended structural motifs”. These motifs originated from wheat A-gliadin and constituted a standard for the analysis of the other proteins. Experiments were carried out based on in silico methods. Analyses covered a total of 403 sequences of selected cereal and seed proteins. Of all the analysed sequences, 155 were found to contain tetrapeptides (potentially known as toxic for celiac disease), namely: QQQP, QQPY, PSQQ, QPYP, including 29 proteins in which the tetrapeptides were constituents of a structural motif with a longer sequence. These were proteins of wheat, barley and oat. All the extended motifs occurred in a hydrophilic surrounding, attaining the structure of beta-turn and random coil. Computer-aided design of the proteolysis process of selected proteins was carried out as well in the aspect of celiac-toxic peptide release. Active fragments were released from twenty-eight proteins by thermolysin, K proteinase and prolyl oligopeptidase.
Background. Proteomic analysis is emerging as a highly useful tool in food research, including studies of food allergies. Two-dimensional gel electrophoresis involving isoelectric focusing and sodium dodecyl sulfate polyacrylamide gel electrophoresis is the most effective method of separating hundreds or even thousands of proteins. In this study, albumin and globulin fractions of pea seeds cv. Ramrod were subjected to proteomic analysis. Selected potentially alergenie proteins were identified based on their molecular weights and isoelectric points. Material and methods. Pea seeds (Pisum sativum L.) cv. Ramrod harvested over a period of two years (Plant Breeding Station in Piaski-Szelejewo) were used in the experiment. The isolated albumins, globulins and legumin and vicilin fractions of globulins were separated by two-dimensional gel electrophoresis. Proteomic images were analysed in the ImageMaster 2D Platinum program with the use of algorithms from the Melanie application. The relative content, isoelectric points and molecular weights were computed for all identified proteins. Electrophoregrams were analysed by matching spot positions from three independent replications. Results. The proteomes of albumins, globulins and legumin and vicilin fractions of globulins produced up to several hundred spots (proteins). Spots most characteristic of a given fraction were identified by Computer analysis and spot matching. The albumin proteome accumulated spots of relatively high intensity over a broad range of pi values of -4.2-8.1 in 3 molecular weight (MW) ranges: I - high molecular-weight albumins with MW of -50-110 kDa, II - average molecular-weight albumins with MW of -20-35 kDa, and III - Iow molecular-weight albumins with MW of-13-17 kDa. 2D gel electrophoregrams revealed the presence of81 characteristic spots, including 24 characteristic of legumin and 14-of vicilin. Conclusions. Two-dimensional gel electrophoresis proved to be a useful tool for identifying pea proteins. Pattems of spots with similar isoelectric points and different molecular weights or spots with different isoelectric points and similar molecular weights play an important role in proteome analysis. The regions characteristic of albumin, globulin and legumin and vicilin fractions of globulin with typical MW and pl values were identified as the results of performed 2D electrophoretic separations of pea proteins. 2D gel electrophoresis of albumins and the vicilin fraction of globulins revealed the presence of 4 and 2 spots, respectively, representing potentially allergenic proteins. They probably corresponded to vicilin fragments synthesized during post-translational modification of the analysed protein.
Celem niniejszej pracy było opracowanie metody identyfikacji frakcji niskocząsteczkowych produktów hydrolizy bydlęcej kazeiny-β przez plazminę za pomocą wysokosprawnej chromatografii cieczowej z odwróconymi fazami (RP-HPLC) w połączeniu ze spektroskopią w nadfiolecie (UV). Bydlęcą kazeinę-β poddano hydrolizie przez plazminę. Supernatant pozostały po wytrąceniu nierozpuszczalnej frakcji hydrolizatu rozdzielono za pomocą ultrafiltracji na retentat zawierający polipeptydy i permeat zawierający peptydy o małej masie cząsteczkowej. Do identyfikacji frakcji permeatu wykorzystano parametry charakteryzujące ilościowo drugie i czwarte pochodne widm UV. Kształt pochodnych widm permeatu wskazywał na obecność niewielkich ilości tryptofanu, który nie został wykryty metodą spektrometrii mas. Wartości parametrów charakteryzujących pochodne widm UV niskocząsteczkowej frakcji hydrolizatu kazeiny-β różnią się w sposób istotny statystycznie (w granicach od p < 0,05 do p < 0,001) od analogicznych parametrów dla pochodnych widm pozostałych frakcji tego hydrolizatu oraz od pochodnych widm białka nie poddanego hydrolizie. Niskocząsteczkowa frakcja hydrolizatu kazeiny-β może być identyfikowana metodą spektroskopii UV.
The objective of this study was to analyse allergenic proteins by identifying their molecular biomarkers for detection in food using bioinformatics tools. The protein and epitope sequences were from BIOPEP database, proteolysis was simulated using BIOPEP program and UniProt database screening via BLAST and FASTA programs. The biomarkers of food proteins were proposed: for example for whey proteins - TPEVD- DEALEKFDKALKALPMHIR (β-Lg: fragment 141-164), chicken egg - AAVSVDCSEYPKPDCTAEDRPL (ovomucoid: 156-177), wheat - KCNGTVEQVESIVNTLNAGQIASTDVVEVWSPPY (triose phosphate isomerase: 12-46) and peanuts - QARQLKNNNPFKFFVPPFQQSPRAVA (arachin: 505-530). The results are annotated in the BIOPEP database of allergenic proteins and epitopes, available at http://www.uwm.edu. pl/biochemia. The epitope-receptor interactions are attributed to the epitope’s sequence and suggest that in silico proteolysis products showing the highest degree of sequence identity with an epitope or its part are characteristic of a given protein or a group of cross-reactive homologs. The protein markers from basic food groups were proposed based on the above assumption.
This review is a brief description of the current state of research on the functional and bioactivite properties of caseins, their hydrolysates and peptides. The functional properties of casein and casein-originated hydrolysates and peptides reflect the natural features of their molecules and environmental characteristics. Many proteolytic enzymes are used for modifying functional and biological properties of caseins. Enzymatic modifications influence the conformation of casein molecules and, in consequence, their properties. The functional properties of caseins may improve upon partial hydrolysis. Peptides derived from casein proteins are capable of affecting the biological functions of an organism. These effects can be antihypertensive, antimicrobial, antithrombotic, immunoregulating and opioid.
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