Formation Of Bioactive Peptides Research Articles

Human colostrum in vitro protein digestion: peptidomics by liquid chromatography-Orbitrap-high-resolution MS and prospection for bioactive peptides via bioinformatics.

Breast milk is known to contain bioactive peptides that are released during digestion, being a major source of bioactive peptides to the new-born, some of which act against invading pathogens. However, the formation of bioactive peptides during digestion of human colostrum remains largely uninvestigated. This study aimed to investigate the formation of peptides during simulated digestion of human colostrum from adult women and to prospect antimicrobial peptides. For this purpose, we used high-resolution MS to monitor the release of peptides during in vitro digestion. Bioinformatics was used for the prospection of antimicrobial activity of peptides. During simulated digestion (oral, gastric and duodenal phases), 2318 peptide sequences derived from 112 precursor proteins were identified. At the end of simulated digestion, casein-derived peptide sequences were the most frequently observed. Among precursors, some proteins were seen for the first time in this study. The resulting peptides were rich in proline, glutamine, valine and leucine residues, providing characteristic traits of antimicrobial peptides. From bioinformatics analysis, seven peptides showed potentially high antimicrobial activity towards bacteria, viruses and fungi, from which the latter was the most prominent predicted activity. Antimicrobial peptides released during digestion may provide a defence platform with controlled release for the new-born.

Extraction of bioactive peptides produced in probiotic yoghurt and determination of their biological activities

This research evaluated the proteolytic activity of Iranian and commercial probiotic strains (e.g., Bifidobacterium lactis, Lactobacillus acidophilus, and Lactobacillus casei) in yoghurt during 28 days of storage. Water-soluble peptides were extracted using high-speed centrifugation. 2,2-Diphenyl-1-picrylhydrazyl (DPPH) and 2,2′-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) methods were used to evaluate the bioactive activities of water-soluble peptide extract (WSPE). Antimutagenic and antibacterial activity against Staphylococcus aureus was investigated using the Ames test and agar gel diffusion method, respectively. There was a direct relationship between formation of bioactive peptides and degree of proteolysis. There was a significant difference between the probiotic and control samples. S. thermophilus + L. bulgaricus + Iranian strain of B. lactis had the highest antioxidant, antimutagenic and antibacterial activities. Therefore, Iranian B. lactis has a high potential for producing bioactive peptides having health benefits in commercial foods such as yoghurt, novel products and therapeutic peptides.

Effect of Lactobacteria on Bioactive Peptides and Their Sequence Identification in Mature Cheese.

An in silico study that featured the effect of starter cultures on the bioactivity and other health benefits of peptides in semi-hard cheese is presented in this contribution. Model Caciotta-type cheese samples were obtained in laboratory conditions in two variations. Sample A included starter cultures of Lactococcus lactis subsp. lactis and Lactococcus lactis subsp. cremoris. Sample B included starter cultures of Lactococcus lactis subsp. lactis, Lactococcus lactis subsp. cremoris, and a culture of lactobacilli Lacticaseibacillus casei. The in silico method showed that the peptides inhibited angiotensin-converting enzymes (ACE) and ipeptidyl peptidase IV (DPP-4), as well as possessed antioxidant properties. Lactococcus lactis subsp. lactis and Lactococcus lactis subsp. cremoris had a greater effect on the formation of bioactive peptides.

Review of the Characterization of Lactic Acid Bacteria in Tuna Fish

Bekasam is a type of fermented freshwater fish product with sour taste. Bekasam is made from fish that have been cleaned gills and entrails, washed, mixed with salt. After 2 days of fermentation, rice is added to this mixture and fermentation is continued for 5 to 7 days. Bekasam is thought to have antihypertensive activity due to the formation of bioactive peptides resulting from fish protein degradation during the fermentation process of the scars. This study aims to isolate indigenous lactic acid bacteria with high power. Lactic acid bacteria were isolated from tuna. Isolation was carried out using MRS agar + CaCO3 medium and screening of proteolytic lactic acid bacterial isolates was carried out using skim agar. Colonies that provide a clear zone on the skim to be identified as lactic acid bacteria. Of the 180 isolates of acid-producing bacteria that provide clear zones in the MRS to find 150 strains of lactic acid bacteria. The results of further morphological and biochemical tests indicate that these isolates are genera Lactobacillus, Pediococccus and Leuconostoc. The results of further selection were carried out on homofermentative lactic acid bacteria and had high proteolytic activity. The results of identification of isolate species using API CH50 showed that selected lactic acid bacteria were Lactobacillus plantarum, Lactobacillus pentosus, and Pediococcus pentosaceus

Can cheese mites, maggots and molds enhance bioactivity? Peptidomic investigation of functional peptides in four traditional cheeses.

Aside from their amino acid content, dairy proteins are valuable for their ability to carry encrypted bioactive peptides whose activities are latent until released by digestive enzymes or endogenous enzymes within the food. Peptides can possess a wide variety of functionalities, such as antibacterial, antihypertensive, and antioxidative properties, as demonstrated by in vitro and in vivo studies. This phenomenon raises the question as to what impact various traditional cheese-making processes have on the formation of bioactive peptides in the resulting products. In this study, we have profiled the naturally-occurring peptides in two hard and two soft traditional cheeses and have identified their known bioactive sequences. While past studies have typically identified fewer than 100 peptide sequences in a single cheese, we have used modern instrumentation to identify between 2900 and 4700 sequences per cheese, an increase by a factor of about 50. We demonstrated substantial variations in proteolysis and peptide formation between the interior and rind of each cheese, which we ascribed to the differences in microbial composition between these regions. We identified a total of 111 bioactive sequences among the four cheeses, with the greatest number of sequences, 89, originating from Mimolette. The most common bioactivities identified were antimicrobial and inhibition of the angiotensin-converting enzyme. This work revealed that cheese proteolysis and the resulting peptidomes are more complex than originally thought in terms of the number of peptides released, variation in peptidome across sites within a single cheese, and variation in bioactive peptides among cheese-making techniques.

Образование биоактивных пептидов под действием микроорганизмов и их идентификация

Образование биоактивных пептидов под действием микроорганизмов и их идентификация

Formation of bioactive peptides during simulated gastrointestinal digestion is affected by αs1-casein polymorphism in buffalo milk

The polymorphism of buffalo αs1-casein has been reported, but little is known about their effect on the biological properties. The objective of this study was to investigate the effect of αs1-casein polymorphism on the digestive properties and bioactivities of buffalo milk protein in simulated gastrointestinal digestion. In this study, two variants of αs1-casein, with one amino acid substitution of Leu193 (AA) → Ser193 (BB), were used. Under acidic gastric conditions, the particle size of αs1-casein variant BB was smaller and showed higher digestibility compared to variant AA. A total of 154 and 149 peptides were identified, respectively, from simulated gastrointestinal digestion of variants AA and BB; of three peptides have been previously reported to exert ACE-inhibition, anticancer, antioxidant, and anxiolytic activities. Our study demonstrated that αs1-casein polymorphism affects the digestive properties and the formation of bioactive peptides.

Effect of cholesterol-lowering starter cultures in smoked sausages on the formation of bioactive peptides and lipid profile in triton-induced hyperlipidemic rats

Three types of sausages were studied: without starter cultures; with experimental starter cultures from Moscow State University of Food Production collection; with starter culture Bactoferm SM 194 (Chr. Hansen). No pathogenic bacteria in any sample were revealed. According to the results of PCR-RT, the number of lactic acid bacteria in all samples was about the same - 1x109-2×109 CFU/g. T-RFLP analysis shows the maximum number of lactobacilli sausages with experimental starter cultures averaged 69.59% of the total microbiota. The study of the protein profile of raw smoked sausages showed changes in protein fractions and presumably formation of biologically active peptides.A wide range of peptide mass peaks, with certain differences, was obtained by mass spectrometry. Feces of rats (groups 1-5) were studied by T-RFLP. The proportion of lactobacilli was 2.09% 2.65% and 2.35%, in groups 3-5 respectively. The serum atherogenic index did not differ significantly between the groups due to the low content of non-LDL and non-HDL cholesterol in control rats compared to the other groups. The greatest decrease of serum cholesterol concentration was measured in rats that consumed sausages with experimental starter cultures, mainly due to almost 3-fold (P<0.05) decrease in cholesterol of low-density lipoproteins compared with the control.

Identification of lactoferrin peptides generated by digestion with human gastrointestinal enzymes

Lactoferrin (LF) is a protein present in milk and other body fluids that plays important biological roles. As part of a diet, LF must survive gastrointestinal conditions or create bioactive fragments to exert its effects. The degradation of LF and formation of bioactive peptides is highly dependent on individual variation in intraluminal composition. The present study was designed to compare the degradation and peptide formation of bovine LF (bLF) following in vitro digestion under different simulated intraluminal conditions. Human gastrointestinal (GI) juices were used in a 2-step model digestion to mimic degradation in the stomach and duodenum. To account for variation in the buffering capacity of different lactoferrin-containing foods, gastric pH was adjusted either slowly or rapidly to 2.5 or 4.0. The results were compared with in vivo digestion of bLF performed in 2 volunteers. High concentration of GI juices and fast pH reduction to 2.5 resulted in complete degradation in the gastric step. More LF resisted gastric digestion when pH was slowly reduced to 2.5 or 4.0. Several peptides were identified; however, few matched with previously reported peptides from studies using nonhuman enzymes. Surprisingly, no bovine lactoferricin, f(17–41), was identified during in vitro or in vivo digestion under the intraluminal conditions used. The diversity of enzymes in human GI juices seems to affect the hydrolysis of bLF, generating different peptide fragments compared with those obtained when using only one or a few proteases of animal origin. Multiple sequence analysis of the identified peptides indicated a motif consisting of proline and neighboring hydrophobic residues that could restrict proteolytic processing. Further structure analysis showed that almost all proteolytic cutting sites were located on the surface and mainly on the nonglycosylated half of lactoferrin. Digestion of bLF by human enzymes may generate different peptides from those found when lactoferrin is digested by nonhuman enzymes. The degradation of LF in the GI tract should be taken into consideration when health effects are proposed, because LF has now been approved by the European Food Safety Authority as a dietary supplement in food products.

Gene expression of prohormone and proprotein convertases in the rat CNS: a comparative in situ hybridization analysis

Posttranslational processing of proproteins and prohormones is an essential step in the formation of bioactive peptides, which is of particular importance in the nervous system. Following a long search for the enzymes responsible for protein precursor cleavage, a family of Kexin/subtilisin-like convertases known as PC1, PC2, and furin have recently been characterized in mammalian species. Their presence in endocrine and neuroendocrine tissues has been demonstrated. This study examines the mRNA distribution of these convertases in the rat CNS and compares their expression with the previously characterized processing enzymes carboxypeptidase E (CPE) and peptidylglycine alpha-amidating monooxygenase (PAM) using in situ hybridization histochemistry. Furin mRNA was ubiquitously distributed and detected both in neurons and non-neuronal tissue throughout the brain with a higher abundance in ependyma, the circumventricular organs, the islands of Calleja, hippocampus, and allocortex. The cellular localization of PC1 and PC2 was exclusively neuronal with highest concentrations in known neuropeptide-rich brain regions. In general, PC2 was more widely expressed than PC1 in the CNS, although many regional variations were detected. The identification of specific combinations of convertase expression together with CPE and PAM expression in neuropeptide-rich brain regions suggests that specific enzymatic pathways are involved in neuropeptide precursor processing, and that these specific combinations are responsible for region-specific differences of posttranslational processing.