Decarboxylation Of Amino Acids Research Articles

Biologically generated carbon dioxide: nature's versatile chemical strategies for carboxy lyases.

Covering: up to 2019Metabolic production of CO2 is natural product chemistry on a mammoth scale. Just counting humans, among all other respiring organisms, the seven billion people on the planet exhale about 3 billion tons of CO2 per year. Essentially all of the biogenic CO2 arises by action of discrete families of decarboxylases. The mechanistic routes to CO2 release from carboxylic acid metabolites vary with the electronic demands and structures of specific substrates and illustrate the breadth of chemistry employed for C-COO (C-C bond) disconnections. Most commonly decarboxylated are α-keto acid and β-keto acid substrates, the former requiring thiamin-PP as cofactor, the latter typically cofactor-free. The extensive decarboxylation of amino acids, e.g. to neurotransmitter amines, is synonymous with the coenzyme form of vitamin B6, pyridoxal-phosphate, although covalent N-terminal pyruvamide residues serve in some amino acid decarboxylases. All told, five B vitamins (B1, B2, B3, B6, B7), ATP, S-adenosylmethionine, manganese and zinc ions are pressed into service for specific decarboxylase catalyses. There are additional cofactor-independent decarboxylases that operate by distinct chemical routes. Finally, while most decarboxylases use heterolytic ionic mechanisms, a small number of decarboxylases carry out radical pathways.

TAAR Agonists.

Trace amine-associated receptors (TAARs) are a family of G protein-coupled receptors (GPCRs) that are evolutionarily conserved in vertebrates. The first discovered TAAR1 is mainly expressed in the brain, and is able to detect low abundant trace amines. TAAR1 is also activated by several synthetic compounds and psychostimulant drugs like amphetamine. Activation of TAAR1 by specific agonists can regulate the classical monoaminergic systems in the brain. Further studies have revealed that other TAAR family members are highly expressed in the olfactory system which are termed olfactory TAARs. In vertebrates, olfactory TAARs can specifically recognize volatile or water-soluble amines. Some of these TAAR agonists are produced by decarboxylation of amino acids. In addition, some TAAR agonists are ethological odors that mediate animal innate behaviors. In this study, we provide a comprehensive review of TAAR agonists, including their structures, biosynthesis pathways, and functions.

EFFECTS OF POPPY OIL ON BIOGENIC AMINE IN FERMENTED TURKISH SAUSAGE

Biogenic amines are generally created by the decarboxylation of amino acids via microbial enzymes and these compounds may have a toxic effect on humans and animals. The ripening and storage conditions of meat and meat products directly affect the quality of such products in terms of biogenic amines. The aim of this study was to investigate the effects of poppy oil, which is produced and consumed in large quantities in Afyonkarahisar province, on the formation of biogenic amines in fermented sausages. In the study, 2 groups of sausages were produced including control and poppy oil groups. 300 mg / kg poppy oil was added to the sausage that would be produced in the poppy oil group. The sausages were ripened for 15 days in the surrounding where relative humidity (90-60%) and the temperature (25-18 ° C) could be adjusted. During this period (0, 2, 4, 6, 8, 10, 13 and 15 days), physico-chemical, sensory, microbiological properties and biogenic amine (histamine, putresin, tryptamine, phenyl ethylamine and tyramine) formations were determined in the samples. As a result, it is recommended that the poppy oil used does not cause a significant difference in the formation of biogenic amines, does not adversely affect the general characteristics of the sausage and that the amount of animal fat is reduced and alternatively, the use of poppy oil in the production of fermented sausage is recommended.

An integrated enrichment-detection platform for identification of contamination of Vibrio parahaemolyticus in food samples

A novel and rapid method to identify contamination of Vibrio parahaemolyticus during an enrichment was developed. The principle was based on the bacteria's capability of carbohydrate fermentation and amino acid decarboxylation. Six different broths were developed with four sugar substrates, namely, dextrose (DEX), arabinose (ARA), mannose (MAO), mannitol (MAI), and two amino acids, namely, lysine (LYS) and ornithine (ODB). Bromocresol purple (BP) and phenol red (PR) were added to detect pH changes of the broths. The absorbance of the color change was determined for all sugar broths at 600 nm and both amino acids at 550 nm. Salinity and pH were adjusted to suppress competitive bacteria. The optimal conditions for the sugar substrates and the amino acids were 8% NaCl/pH = 9.0 and 6% NaCl/pH = 6.0, respectively. In real samples, this method was capable of detecting V. parahaemolyticus with a limit of detection of 0.1–1.0 log CFU/mL (measured as an initial cell concentration in the samples). At 24 h, this method also yielded a 100% sensitivity and improved a specificity to 95%–100%, compared to the 88% specificity as obtained in the conventional method. Integrating the detection of V. parahaemolyticus provided a quick and effective screening for the presence of V. parahaemolyticus.

Stable carbon isotope diagnostics of mammalian metabolism, a high-resolution isotomics approach using amino acid carboxyl groups.

The carbon isotopic compositions of amino acids are increasingly measured to characterize diets and metabolic response to diets. We report a new high-resolution system to measure the stable carbon isotopic composition of carboxyl atoms within amino acids. The automated system used HPLC to separate amino acids followed by addition of ninhydrin for decarboxylation and transfer of the evolved CO2 to a stable isotope ratio mass spectrometer for δ13CCARBOXYL measurement. The ninhydrin reaction was conducted at acidic pH (1.5) and elevated temperature (160 oC) giving yields close to 100% for most common amino acids. Eight mammalian keratin samples from herbivores (kudu and caribou), omnivores (humans) and carnivores (bowhead and humpback zooplanktivorous whales) were analysed with this new system. The data provide an initial calibration of reference materials to be used in studies of this type and is the first report of carboxyl carbon isotope distributions in mammals. Results showed widespread 13C enrichments in both essential and non-essential amino acid carboxyl groups, likely linked to decarboxylation of amino acids during normal metabolism. Analyses of non-essential amino acid isotope profiles showed (1) consistent and general taxon-level metabolic differences between the herbivore, human and whale samples, (2) marked differences among individual humans, ruminants and whales (3) evidence for gluconeogenesis in the wildlife samples, and (4) extensive 13C enrichment likely associated with fasting in the humpback whale sample. Future mammalian research related to the metabolism of growth, reproduction, aging and disease may benefit from using this technique. Values obtained for internationally available samples USGS42 and USGS43 (Tibetan and Indian human hair) provide a first characterization of reference materials for δ13CCARBOXYL profiles.

The effect of reduction of NaCl content on selected parameters during ripening of cheese

The aim of this work was to observe chemical and physical changes in Dutch-type cheese during ripening depending on salt concentration. Ripening is one of the most important factors influencing the sensory quality of cheese and therefore the cheese production should be studied. Among the substances which are formed during ripening belong the biogenic amines which are produced by the decarboxylation of amino acids. These amino acids are created during proteolysis. The salt content largely affects the intensity of the ripening process, but also other cheese parameters such as dry matter content, hardness or content of biogenic amines. In the course of 3 months ripening of model cheeses with different cultures and with different salt content, the effect of the salt on pH, dry matter content, free amino acids and biogenic amines content and hardness was monitored. The concentration of NaCl affected the dry matter content and the hardness of the samples. The reduction in salt content contributes to the higher accumulation of biogenic amines during ripening.

Innovative Approaches for the Degradation of Biogenic Amines in Foods

Biogenic Amines (BA) are low molecular weight organic bases that have biological activity, they can be formed and degraded as a result of normal metabolic activity in animals, plants and microorganisms, and are usually produced by the decarboxylation of amino acids. The most common biogenic amines which can be found in foods are aliphatic (putrescine, cadaverine, spermine, spermidine), aromatic (tyramine, phenylethyl amine) or heterocyclic (histamine, tryptamine) structures.

Organocatalytic Decarboxylation of Amino Acids as a Route to Bio‐based Amines and Amides

AbstractAmino acids obtained by fermentation or recovered from protein waste hydrolysates represent an excellent renewable resource for the production of bio‐based chemicals. In an attempt to recycle both carbon and nitrogen, we report here on a chemocatalytic, metal‐free approach for decarboxylation of amino acids, thereby providing a direct access to primary amines. In the presence of a carbonyl compound the amino acid is temporarily trapped into a Schiff base, from which the elimination of CO2 may proceed more easily. After evaluating different types of aldehydes and ketones on their activity at low catalyst loadings (≤5 mol%), isophorone was identified as powerful organocatalyst under mild conditions. After optimisation many amino acids with a neutral side chain were converted in 28–99 % yield in 2‐propanol at 150 °C. When the reaction is performed in DMF, the amine is susceptible to N‐formylation. This consecutive reaction is catalysed by the acidity of the amino acid reactant itself. In this way, many amino acids were efficiently transformed to the corresponding formamides in a one‐pot catalytic system.

A review of pretreatment and analytical methods of biogenic amines in food and biological samples since 2010

Biogenic amines (BAs), mainly produced by amino acid decarboxylation, are widespread in foods and human organisms. Appropriate intake of BAs is beneficial to the human body, while excessive consumption may cause discomfort. Meanwhile, BAs are a kind of chemical marker for evaluating meat freshness. For these reasons, simple, rapid and efficient methods have been developed for the determination of BAs in food and biological products. This review introduces the provenance, classification and physiological activity of eight essential BAs and summarizes the dominant pretreatment and analysis methods since 2010. Pretreatment technologies mainly include the “dilute and shoot” method, ultrasonic assisted extraction, solid-phase extraction, matrix solid-phase dispersion, dispersive liquid-liquid microextraction, etc. Determination methods include liquid chromatography coupled to ultraviolet or fluorescence detectors, liquid chromatography tandem mass spectrometry, capillary electrophoresis, biosensors and so on.

Biogenic Amines Determination in “Plant Milks”

“Plant milks” are water-based beverages, such as, extracts from cereals, pseudo-cereals, oil seeds, legumes or fruits. Plant milk consumption is rising in European and North American markets due to problems related to cow milk allergies, intolerances, but also because of vegan diets and sensitivity to environmental issues. There is no specific regulation for these beverages, therefore their composition can vary considerably, even in the same category. The aim of this study is to characterize the main categories of cereal and pseudo-cereal milks on the market by studying the profile of 8 biogenic amines (histamine, serotonin, spermine, spermidine, putrescine, β-phenylethylamine, cadaverine, tyramine) through a RP-HPLC/FD method with a pre-column derivatization. Biogenic amines are ubiquitous compounds, produced by the decarboxylation of the respective amino acids and they have been proposed as quality and safety markers of different foods and beverages. In the analyzed samples, the total biogenic amines content ranged from a minimum of 1.92 mg/L, to a maximum of 9.27 mg/L. The main biogenic amine found in the samples was histamine. The results show a low content of biogenic amines in all types of analyzed products. This ensures the quality and safety of cereal and pseudo-cereal milk samples.

Декарбоксилирование 2'-дикарбокси-5-(метил-5'индолил-3')-индолил-3-уксусной кислоты с использованием одновалентной меди

In this article a decarboxylation method based on the use of quinoline with a copper salt is discussed. Decarboxylation is the elimination of CO2 from the carboxylic group of carboxylic acids or the carboxylate group of their salts. The process is used to produce a large number of organic compounds, such classes as alkanes, alkenes, alcohols, ketones, ethers and esters. Decarboxylation plays an important role in the metabolism of living organisms, namely in the decarboxylation of amino acids. From this we can conclude that the process is important to study. Decarboxylation proceeds in different ways. The most common methods of decarboxylation includes heating in various conditions. For example, such as heating in the presence of acids and alkalis, under severe conditions with quinoline, thermal oxidation in the presence of transition metal salts, Kolbe reaction. In the procces of the CO2 removal group in relation to amino acids there are several types: α-decarboxylation, decarboxylation, associated with the trans-amination reaction and the condensation reaction of molecules. In the synthesis of substituted auxin 2'-dicarboxy-5-(methyl-5'indolyl-3')-indolyl-3-acetic acid, the yield of the product was not high. The usual heating in the presence of alkali output was less than 5%, and in this work it was decided to use other methods of decarboxylation to increase the yield of the product. The aim of the work is to improve the method of decarboxylation of carboxyindolyl substrates for increasing product yield and to compare with the result obtained by ordinary heating of this substances in the presence of alkali. At the end of the work summed up. Found the optimal conditions for the process of decarboxylation of investigated substrates. Optimal conditions chosen based on product yield. To confirm the chemical structures of the substances, 1H NMR, IR spectroscopy, and elemental analysis were used.

Determination of target biogenic amines in fish by GC-MS: investigating seafood quality

Introduction: Worldwide there is a strong requirement for food quality and safety [1], with the chemical and biological nature of hazards being the major concern. Fish degradation is a complex phenomenon where a series of events occur simultaneously, influencing each other and beginning immediately at the time of death [1]. Consequently, a reliable fish quality analysis is essential for consumer protection. Thus, the main aim of the present study was to develop an analytical approach based on sample treatment and GC-MS methodologies to detect biogenic amines as products of seafood degradation. Materials and methods: For the GC-MS analysis two Atlantic fish species were selected (Trachurus trachurus and Sarda sarda). The fish were fileted and exposed to room temperature for 9 days (T. trachurus) and 13 days (S. sarda). Samples were collected every day and frozen (-80ºC) for later analysis. Following the periods of exposure, stored samples, were homogenized in 75:25 Methanol: 0,4N HCl. Then, samples were treated and analyzed by GC-MS as described by Richard et al. [2]. Results: The results show that biogenic amines arise after two days of exposure in analysed fish samples. Following GC-MS analysis, putrescine, tyramine, spermine and spermidine emerged in two days and cadaverine and phenylethylamine after four days of exposure. However, cadaverine, spermine and spermidine decreased below LD (limit of detection) after nine days of exposure showing a different profile over exposure time. Discussion and conclusions: The different biogenic amines profile found is compatible with the bacterial activity in sea food, namely biogenic amines which are usually produced by decarboxylation of free amino acids and transamination of aldehydes and ketones by the action of diverse microorganisms. Moreover, although GC-MS seems to be reliable technique to analyse biogenic amines in seafood samples more analysis should be performed focused on other sample treatment methodologies and cross-checking with other analytical techniques (e.g. LC-MS/MS and HPLC) until validation.

Biogenic Amines as Risk Factors of Food Chain

Biogenic amines at higher doses have negative effects on the human organism. Some biogenic amines (e.g. putrescine, spermine, spermidine, cadaverine, histamine) are an essential component of living cells because they are involved in the regulation of nucleic acid and protein synthesis and membrane stabilization. Amines are produced by the decarboxylation of natural free amino acids. Decarboxylases are not common in bacteria but occur in species of many genera, particularly in Bacillus, Citrobacter, Clostridium, Escherichia, Klebsiella, Photobacterium, Proteus, Pseudomonas, Salmonella, Shigella and lactic bacteria of the Lactobacillus genera, Pediococcus and Streptococcus. Main factors influencing the biogenic amines formation are pH, water activity, storage time, temperature and salt content. Typical levels of biogenic amines in foods range from 10 mg/kg to 100 mg/kg. Occasionally, the amount of biogenic amines in food can exceed 1000 mg/kg.

ЩОДО ПИТАННЯ ПРО УТВОРЕННЯ БІОГЕННИХ АМІНІВ У ХАРЧОВИХ ПРОДУКТАХ

У статті показано, що особливої популярності останнім часом набувають фермен-товані продукти. Однак у процесі виробництва зрілих вин, сирів, ковбас і багатьох рибних продуктів утворюються біогенні аміни в результаті декарбоксилювання вільних амінокислот під дією ферментних систем мікробного походження при порушенні умов зберігання. Біогенні аміни - це група азотовмісних органічних сполук з аліфатичною (путресцин, кадаверин, спермін, спермидин), ароматичною (тирамін, фенілетиламін) або гетероциклічною (гістамін, триптаміну) структурою. Деякі з них мають велику біологічну активність (гістамін, серотонін, дофамін, тирамін), інші (путресцин і кадаверин) підсилюють токсичну дію гістаміну на організм людини. В окремих випадках, коли вміст гістаміну в десятки разів перевищує гранично допустимий рівень, риба може набувати гострого смаку. Отруєння гістаміном можуть мати летальний результат. Аналіз літературних даних показав, що до причин утворення біогенних амінів відносять: мікробіологічну якість вихідної сировини, умови і терміни зберігання сировини і готової продукції, наявність декарбоксілазно позитивних мікроорганізмів.

Biogenic Amine Production by Lactic Acid Bacteria: A Review.

Lactic acid bacteria (LAB) are considered as the main biogenic amine (BA) producers in fermented foods. These compounds derive from amino acid decarboxylation through microbial activities and can cause toxic effects on humans, with symptoms (headache, heart palpitations, vomiting, diarrhea) depending also on individual sensitivity. Many studies have focused on the aminobiogenic potential of LAB associated with fermented foods, taking into consideration the conditions affecting BA accumulation and enzymes/genes involved in the biosynthetic mechanisms. This review describes in detail the different LAB (used as starter cultures to improve technological and sensorial properties, as well as those naturally occurring during ripening or in spontaneous fermentations) able to produce BAs in model or in real systems. The groups considered were enterococci, lactobacilli, streptococci, lactococci, pediococci, oenococci and, as minor producers, LAB belonging to Leuconostoc and Weissella genus. A deeper knowledge of this issue is important because decarboxylase activities are often related to strains rather than to species or genera. Moreover, this information can help to improve the selection of strains for further applications as starter or bioprotective cultures, in order to obtain high quality foods with reduced BA content.

Histamin u ribi dostupnoj na tržištu Srbije u 2018. godini

Histamine is a biogen amin, which is formed by decarboxylation of the histidine amino acid, under the action of the L-histidine-decarboxylase enzyme. High level of free histidine in fish meat, bacterial histidin decarboxylase activity and high temperature of storage elevate the level of histamine. Among the most important factors that can affect the level of histamine in fish meat are the type of fish and the method of its preservation. In order to determine this dependence, 1030 samples of frozen fish (tuna, mackerel, sardines and sprat) and 167 samples of canned fish (tuna, sardines and mackerel) were monitored for histamine content by ELISA method. It was determined a lower concentration of histamine in frozen fish (from 5.71 mg/kg to 18.03 mg/kg) compared to canned fish (from 15.03 mg/kg to 110.6 mg/kg). The highest histamine concentrations were found in the mackerel samples, regardless of the preservation method (110.6 mg/kg in canned mackerel and 18.03 mg/kg in frozen mackerel), which were significantly higher compared to the histamine levels found in cans of tuna and sardines (p ˂0.0001). Of the total number of samples, three samples (two samples of canned sardines and one sample of canned mackerel) were declared unsafe for human health. In most of the analyzed samples, the level of determined histamine was relatively low, which confirms adequate implementation of control protocols and efficant surveillance of products placed on the Serbian market.

Probiotic potential and biochemical and technological properties of Lactococcus lactis ssp. lactis strains isolated from raw milk and kefir grains

Lactococcus lactis ssp. lactis is one of the most important starter bacteria used in dairy technology and it is of great economic importance because of its use in the production of dairy products, including cheese, butter, cream, and fermented milks. Numerous studies have evaluated the biochemical and probiotic properties of lactococci; however, limited studies on the probiotic characteristics of lactococci were conducted using strains originating from raw milk and dairy products. Characterizing the probiotic properties of strains isolated from raw milk and fermented milk products is important in terms of selecting starter culture strains for the production of functional dairy products. In this study, biochemical properties (including antibiotic sensitivity, lipolytic activity, amino acid decarboxylation, antioxidant activity) and probiotic properties (including antimicrobial activity, growth in the presence of bile salts, bile salts deconjugation, and hydrophobicity) of 14 Lactococcus lactis strains isolated from raw milk and kefir grains were investigated. Strains originating from kefir grains had better characteristics in terms of antimicrobial activity and bile salt deconjugation, whereas strains from raw milk had better hydrophobicity and antioxidant activity characteristics. None of the strains were able to grow in the presence of bile salt and did not show amino acid decarboxylation or lipolytic activities. Biochemical and probiotic properties of L. lactis strains varied depending on the strain and some of these strains could be used as functional cultures depending on their properties. However, these strains did not possess all of the properties required to meet the definition of a probiotic.

Gıdalarda Mikrobiyel Faliyetler Sonucu Oluşan Biyojen Aminler

Biyojen aminler, amino asitlerin mikrobiyel dekarboksilasyonu yoluyla veya aldehit ve ketonların aminasyonu ve transaminasyonu yoluyla oluşan, başta proteince zengin gıdalar olmak üzere birçok gıdada bulunabilen azotlu organik bileşiklerdir. Enterococcus, Lactobacillus, Leuconostoc ve Enterobacteriaceae ailesi gibi dekarboksilaz pozitif mikroorganizmaların gıdalardaki faaliyetleri sonucunda oluşmaktadırlar. Histamin, tiramin, putresin, kadaverin, triptamin, β-feniletilamin, spermin ve spermidin gıdalarda en fazla bulunan biyojen aminler arasındadır. Biyojenaminler yüksek konsantrasyonlarda alındıklarında toksik etki göstermekte ve hipo- ve hipertansiyon, migren, mide bulantısı, kusma, ateş ve solunum sıkıntısı gibi gıda zehirlenmesi semptomları benzeri önemli sağlık sorunlarına neden olabilmektedirler. Biyojen aminlerin sahip oldukları bu toksik etkilere rağmen, gıdalarda bulunma limitlerine dair henüz ortak bir yasal düzenleme bulunmamaktadır. Günümüzde güvenli gıdalara olan ilginin giderek artması, biyojen amin gibi bileşiklerin tespit edilmesini zorunlu hale getirmiştir. Bu amaçla son yıllarda birçok moleküler tabanlı teknik geliştirilmiştir. Bu derlemede, mikrobiyel faaliyetler sonucu oluşan biyojen aminler ele alınmış olup, bu biyojen aminlerin bulundukları gıda grupları ve sağlık üzerine etkileri incelenmiştir.

Effect of In Vitro Human Digestion on Biogenic Amine (Tyramine) Formation in Various Fermented Sausages

Biogenic amines are formed in various fermented foods by microbial amino acid decarboxylation activities, and ingestion of these amines may cause human illness. However, the effect of digestion on the biogenic amines in fermented sausages has not been studied. This study was conducted to determine the effect of in vitro human digestion with the enterobacteria Escherichia coli and Lactobacillus casei on concentrations of the biogenic amine tyramine in six types of fermented sausages. Tyramine concentration was not significantly changed until simulated digestion in the small intestine. However, tyramine concentration for all sausage samples was increased after simulated digestion in the large intestine. Addition of E. coli and L. casei dramatically increased the tyramine concentrations ( P < 0.05). This result indicates that enterobacteria increase biogenic amine concentrations during human digestion.

Rapid sensing of l-leucine by human and murine hypothalamic neurons: Neurochemical and mechanistic insights

ObjectiveDietary proteins are sensed by hypothalamic neurons and strongly influence multiple aspects of metabolic health, including appetite, weight gain, and adiposity. However, little is known about the mechanisms by which hypothalamic neural circuits controlling behavior and metabolism sense protein availability. The aim of this study is to characterize how neurons from the mediobasal hypothalamus respond to a signal of protein availability: the amino acid l-leucine. MethodsWe used primary cultures of post-weaning murine mediobasal hypothalamic neurons, hypothalamic neurons derived from human induced pluripotent stem cells, and calcium imaging to characterize rapid neuronal responses to physiological changes in extracellular l-Leucine concentration. ResultsA neurochemically diverse subset of both mouse and human hypothalamic neurons responded rapidly to l-leucine. Consistent with l-leucine's anorexigenic role, we found that 25% of mouse MBH POMC neurons were activated by l-leucine. 10% of MBH NPY neurons were inhibited by l-leucine, and leucine rapidly reduced AGRP secretion, providing a mechanism for the rapid leucine-induced inhibition of foraging behavior in rodents. Surprisingly, none of the candidate mechanisms previously implicated in hypothalamic leucine sensing (KATP channels, mTORC1 signaling, amino-acid decarboxylation) were involved in the acute activity changes produced by l-leucine. Instead, our data indicate that leucine-induced neuronal activation involves a plasma membrane Ca2+ channel, whereas leucine-induced neuronal inhibition is mediated by inhibition of a store-operated Ca2+ current. ConclusionsA subset of neurons in the mediobasal hypothalamus rapidly respond to physiological changes in extracellular leucine concentration. Leucine can produce both increases and decreases in neuronal Ca2+ concentrations in a neurochemically-diverse group of neurons, including some POMC and NPY/AGRP neurons. Our data reveal that leucine can signal through novel mechanisms to rapidly affect neuronal activity.