Types Of Amino Acids Research Articles

PH-Dependent proteolytic activity of histidine-pendant polyacrylamides

Artificial enzymes with serine, aspartic acid, and histidine that mimic the catalytic triad of serine proteases have been studied. However, they were mainly investigated for their cleavage activity on low molecular-weight esters and amides, and there has been a lack of knowledge about their protein cleavage activity. We previously found that not only ternary polyacrylamides with serine, aspartic acid, and histidine but also homo-polyacrylamides with a single type of amino acid cleaved bovine and human serum albumins. These results suggested that the carboxy group, a common functional group in active polymers, may be involved in the expression of activity. In this study, we synthesized histidine polymers in which the carboxy group was changed to a carboxamido or amino group and investigated the relationships between structure and activity. Histidine homopolymers and histidine-acrylamide copolymers were incubated with bovine serum albumin at 37 °C for one week under different pH conditions and then analyzed by sodium dodecyl-sulfate polyacrylamide gel electrophoresis. In the case of histidine homopolymers, the carboxy-type homopolymers were active under weakly acidic to neutral conditions, while the carboxamido- and amino-type homopolymers were not active regardless of liquid properties. In the case of histidine-acrylamide copolymers, their activity was essentially the same as that of each type of histidine homopolymer, but for all types of copolymers, activity appeared under weakly basic conditions when the histidine monomer units were of a specific density. The carboxy-type copolymers with dual-mode activity showed different degradation patterns of bovine serum albumin under acidic and basic conditions. The structural features common to the active homopolymers and copolymers suggested that the carboxy group contributes to the activity under weakly acidic to neutral conditions, while the imidazole group of the histidine side chain and its density contribute to the activity under weakly basic conditions.

Hydrogen bonds of a water molecule in the second coordination sphere of amino acid metal complexes: influence of amino acid types on different complex geometries

Quantum chemical calculations at the M06L-GD3/def2-TZVPP level were done to investigate hydrogen bonds between amino acid metal complexes and a free water molecule. Octahedral nickel(II) and square planar palladium(II) complexes of glycine, cysteine, phenylalanine, and serine with different charges of metal complexes (+1, 0, and −1) were investigated. The following hydrogen bonds were considered: NH/O (amino acid is a H-donor), O1/HO (coordinated O1 oxygen from amino acid is a H-acceptor), and O2/HO (non-coordinated O2 oxygen from amino acid is a H-acceptor). Amino acid type has a small influence on interaction energies, both for octahedral nickel(II) and square planar palladium(II) complexes. The influence is the largest for NH/O and the smallest for O2/HO hydrogen bonds. For NH/O interaction, palladium(II) complexes showed stronger hydrogen bonds than nickel(II), up to −11.8 kcal mol−1 for singly positively charged complexes. Nickel(II) complexes demonstrated higher O1/HO hydrogen bond strength than palladium(II) with interaction energies up to −8.9 kcal mol−1 for singly negative complexes. With up to −9.0 kcal mol−1 interaction energy for singly negative complexes, O2/HO interactions were also stronger for nickel(II) complexes than palladium(II).

An Analysis of Essential Amino Acid Contents of Canistel Fruit (Pouteria campechiana) as A Source of Vegetable Protein in An Effort of Food Diversification

Canistel fruit is a fruit that is not cultivated and is not known to many people because of limited information about this fruit. In the field of biochemistry, analysis of the essential amino acids contained in canistel fruit has never been carried out. The aim of this research is to determine the type and levels of essential amino acids in Canistel fruit as a source of vegetable protein in an effort to diversify food. The sample used was Canistel fruit. The method used was chromatography using UPLC with a C18 column, PDA detector, gradient pump system, and column temperature of 49⁰C. 15 types of amino acids were obtained, consisting of 7 essential amino acids and 8 non-essential amino acids. Essential amino acids are L-Fenilalanin (994,64 mg/kg), L- Isoleusin (704,58 mg/kg), L-Valin (876,69 mg/kg), L-Lisin 1.068,36 mg/kg), L- Leusin (1.199,45 mg/kg), L-Treonin (857,16 mg/kg), and LHistidin (421,03 mg/kg)and 8 non-essential amino acid are L-Serin (957,38 mg/kg), L-Asam glutamat (2.137,7 mg/kg), L-Alanin (1.070,01 mg/kg), LArginin (838,15 mg/kg), L-Glisin (1.101,56), L-asam aspartate (1.900,63 mg/kg), L-Tirosin (141,90 mg/kg), and L-Prolin (1.146,84 mg/kg).

Structure, dynamics, and redox reactivity of an all-purpose flavodoxin

The flavodoxin of Rhodopseudomonas palustris CGA009 (Rp9Fld) supplies highly reducing equivalents to crucial enzymes such as hydrogenase, especially when the organism is iron-restricted. By acquiring those electrons from photodriven electron flow via the bifurcating electron transfer flavoprotein (ETF), Rp9Fld provides solar power to vital metabolic processes. To understand Rp9Fld's ability to work with diverse partners, we solved its crystal structure. We observe the canonical flavodoxin (Fld) fold and features common to other long-chain Flds, but not all the surface loops thought to recognize partner proteins. Moreover some of the loops display alternative structures and dynamics. To advance studies of protein-protein associations and conformational consequences, we assigned the 19F NMR signals of all 5 tyrosines (Tyrs). Our electrochemical measurements show that incorporation of 3-19F-Tyr in place of Tyr has only a modest effect on Rp9Fld's redox properties even though Tyrs flank the flavin on both sides. Meanwhile, the 19F probes demonstrate the expected paramagnetic effect, with signals from nearby Tyrs becoming broadened beyond detection when the flavin semiquinone is formed. However the temperature dependencies of chemical shifts and linewidths reveal dynamics affecting loops close to the flavin, and regions that bind to partners in a variety of systems. These coincide with patterns of amino acid type conservation but not retention of specific residues, arguing against detailed specificity with respect to partners. We propose that the loops surrounding the flavin adopt altered conformations upon binding to partners and may even participate actively in electron transfer.

Opposing genetic polymorphisms of two ABC transporters contribute to the variation of nukacin resistance in Streptococcus mutans.

Streptococcus mutans is an important pathogenic bacterium not only for dental caries but also for systemic diseases. S. mutans is known to produce a variety of bacteriocins and to retain resistance these bacteriocins. In this study, two ABC transporters, LctFEG and MukFEG, were implicated in nukacin resistance and each ABC transporter has two subtypes, active and inactive. Of the two ABC transporters, only one ABC transporter was always resistant, while the other ABC transporter was inactivated by genetic mutation. Interestingly, this phenomenon was defined by the presence or absence of the mutacin K8 synthesis gene region, one of the bacteriocins of S. mutans. This suggests that the resistance acquisition is tightly controlled in each strain. This study provides important evidence that the insertion of bacteriocin synthesis genes is involved in the induction of genetic polymorphisms and suggests that bacteriocin synthesis genes may play an important role in bacterial evolution.

Unveil the sugar diet and associated environmental compounds in the crop of the mosquito Culex pipiens

Culex pipiens (Linnaeus, 1758) mosquitoes search plant sources of sugars to cope with the energetic demand of various physiological processes. The crop as part of the digestive system is devoted to the storage of sugar-based meal obtained from various nectars sources. The profiling of sugars and metabolites in the Culex pipiens’ crop is scarce, and only few studies used Liquid Chromatography – Mass Spectrometry (LC-MS), which provides broad detection for biomonitoring environmental substances and even contaminants in the sugar diet of mosquitoes populations.Therefore, sugar and metabolite profiling were performed on crops obtained from mosquitoes exposed to plant nectar under laboratory or natural conditions by Ultra High-Performance LC-MS (UHPLC-MS). This method allowed us a precise quantitative and qualitative identification of sugar diet and associated environmental compounds in the crop of the mosquito C. pipiens. Under laboratory condition, mosquitoes were allowed to feed on either glucose solution, commercially-available flowers or field collected flowers. In addition, we collected mosquitoes from the field to compare those crop metabolomes with metabolome patterns occurring after nectar feeding in the lab.The sugar quantities and quality obtained from the crops of mosquitoes collected in the field were similar to those crops obtained from mosquitoes that fed on commercially-available flowers and from field collected flowers with a limit of detection of 10 μg/L for sucrose, glucose and sucrose. Next to sugar compounds, we identified 2 types of amino acids, 12 natural products, and 9 pesticides.Next to the diversity of sugar compounds, we could confirm that secondary metabolites and environmental pollutants are typically up taken from floral nectar sources by C. pipiens. The in-depth knowledge on mosquito–plant interactions may inspire the development and further optimization of mosquito trap systems and arboviral surveillance systems.

ANALISIS PEMBUATAN DAN POTENSI EKOENZIM KULIT BUAH JERUK NIPIS (Citrus aurantiifolia) SEBAGAI UPAYA PENINGKATAN KESEHATAN MANDIRI RUMAH TANGGA

Lime peel ecoenzyme (Citrus aurantifolia) is a microbial-based product made by fermenting the fruit peel for more than one month. The study aimed to analyze the ecoenzyme product from lime peel (C. aurantifolia) and its potential as an antiseptic so that it becomes one of the independent health improvement efforts on a household scale. The research design was laboratory experiments. The data described descriptively based on the results obtained from laboratory experiments. The research results showed that ecoenzyme contains a complex of organic ingredients as a natural antiseptic that can be used in the household such as 19 types of organic acids, 17 types of flavonoids, 16 types of carbohydrates and 19 types of amino acids which have potential as antiseptics. The study concluded that the ecoenzyme product from lime peel (C. aurantifolia) has potential as an antiseptic because it contains a complex of organic ingredients as a natural antiseptic that can be used in the household. Potential antiseptics can be in the form of dish cleaners, fruit and vegetable washes. Instead of being an antiseptic, ecoenzyme liquid can be used as a plant fertilizer and compost activator which can be applied to reduce household waste.

Changes and correlation analysis of volatile flavor compounds, amino acids, and soluble sugars in durian during different drying processes

Durian contains rich flavor components that undergo complex changes during drying. In this study, durian was subjected to integrated freeze-drying (IFD), conventional freeze-drying (CFD), and hot air drying (AD). Compared with the fresh samples, those dried by IFD, CFD, and AD lost 11, 9, and 7 original volatile compounds, respectively, and generated 7, 6, and 8 new volatile compounds, respectively, and showed a rapid and then slow decreasing trend in the total content during drying. However, the types of amino acids and soluble sugars remained unchanged during each of the drying methods. Furthermore, volatile compounds showed a significant negative correlation with the majority of amino acids and a significant positive correlation with soluble sugars. The IFD samples had the highest content of volatile compounds, amino acids, and soluble sugars. Therefore, IFD is recommended as a preferable drying method for durian.

Using quantum annealing to design lattice proteins

Quantum annealing has shown promise for finding solutions to difficult optimization problems, including protein folding. Recently, we used the D-Wave Advantage quantum annealer to explore the folding problem in a coarse-grained lattice model, the HP model, in which amino acids are classified into two broad groups: hydrophobic (H) and polar (P). Using a set of 22 HP sequences with up to 64 amino acids, we demonstrated the fast and consistent identification of the correct HP model ground states using the D-Wave hybrid quantum-classical solver. An equally relevant biophysical challenge, called the protein design problem, is the inverse of the above, where the task is to predict protein sequences that fold to a given structure. Here, we approach the design problem by a two-step procedure implemented and executed on a D-Wave machine. In the first step, we perform a pure sequence-space search by varying the type of amino acid at each sequence position, and seek sequences which minimize the HP-model energy of the target structure. After mapping this task onto an Ising spin-glass representation, we employ a hybrid quantum-classical solver to deliver energy-optimal sequences for structures with 30–64 amino acids, with a 100% success rate. In the second step, we filter the optimized sequences from the first step according to their ability to fold to the intended structure. In addition, we try solving the sequence optimization problem using only the quantum processing unit (QPU), which confines us to sizes ≤20, due to exponentially decreasing success rates. To shed light on the pure QPU results, we investigate the effects of control errors caused by an imperfect implementation of the intended Hamiltonian on the QPU, by numerically analyzing the Schrödinger equation. We find that the simulated success rates in the presence of control noise semiquantitatively reproduce the modest pure QPU results for larger chains. Published by the American Physical Society 2024

Effect of Amino Acid Types on the Mechanical and Antimicrobial Properties of Amino Acid-Based Polyionic Liquid Hydrogels.

Polyionic liquid hydrogels attract increasing attention due to their unique properties and potential applications. However, research on amino acid-based polyionic liquid hydrogels is still in its infancy stage. Moreover, the effect of amino acid types on the properties of hydrogels is rarely studied to date. In this work, amino acid-based polyionic liquid hydrogels (D/L-PCAA hydrogels) are synthesized by copolymerizing vinyl choline-amino acid ionic liquids and acrylic acids using Al3+ as a crosslinking agent and bacterial cellulose (BC) as a reinforcing agent. The effects of amino acid types on mechanical and antimicrobial properties are systematically investigated. D-arginine-based hydrogel (D-PCArg) shows the highest tensile strength (220.7 KPa), D-phenylalanine-based hydrogel (D-PCPhe) exhibits the highest elongation at break (1346%), and L-aspartic acid-based hydrogel (L-PCAsp) has the highest elastic modulus (206.9 KPa) and toughness (1.74MJ m-3). D/L-PCAsp hydrogels demonstrate stronger antibacterial capacity against Escherichia coli and Staphylococcus aureus, and D/L-PCPhe hydrogels possess higher antifungal activity against Cryptococcus neoformans. Moreover, the resultant hydrogels exhibit prominent hemocompatibility and low toxicity, as well as excellent self-healing capabilities (86%) and conductivity (2.8 S m-1). These results indicate that D/L-PCAA hydrogel provides a promise for applications in wound dressings.

Most Monogenic Disorders Are Caused by Mutations Altering Protein Folding Free Energy.

Revealing the molecular effect that pathogenic missense mutations have on the corresponding protein is crucial for developing therapeutic solutions. This is especially important for monogenic diseases since, for most of them, there is no treatment available, while typically, the treatment should be provided in the early development stages. This requires fast targeted drug development at a low cost. Here, we report an updated database of monogenic disorders (MOGEDO), which includes 768 proteins and the corresponding 2559 pathogenic and 1763 benign mutations, along with the functional classification of the corresponding proteins. Using the database and various computational tools that predict folding free energy change (ΔΔG), we demonstrate that, on average, 70% of pathogenic cases result in decreased protein stability. Such a large fraction indicates that one should aim at in silico screening for small molecules stabilizing the structure of the mutant protein. We emphasize that knowledge of ΔΔG is essential because one wants to develop stabilizers that compensate for ΔΔG, but do not make protein over-stable, since over-stable protein may be dysfunctional. We demonstrate that, by using ΔΔG and predicted solvent exposure of the mutation site, one can develop a predictive method that distinguishes pathogenic from benign mutations with a success rate even better than some of the leading pathogenicity predictors. Furthermore, hydrophobic-hydrophobic mutations have stronger correlations between folding free energy change and pathogenicity compared with others. Also, mutations involving Cys, Gly, Arg, Trp, and Tyr amino acids being replaced by any other amino acid are more likely to be pathogenic. To facilitate further detection of pathogenic mutations, the wild type of amino acids in the 768 proteins mentioned above was mutated to other 19 residues (14,847,817 mutations), the ΔΔG was calculated with SAAFEC-SEQ, and 5,506,051 mutations were predicted to be pathogenic.

Study on the Modification and Properties of Silk Sericin Protein/Nano-Titanium Dioxide Composite for Textile Applications

Abstract Silk sericin protein is a natural high-molecular-weight compound that contains eighteen types of amino acids. It is non-toxic, biodegradable, and biocompatible, with simple preparation methods and low cost. It finds widespread application in functional clothing, medical and pharmaceutical fields, tissue engineering, and more. Nano-titanium dioxide, on the other hand, possesses non-toxic, self-cleaning, antibacterial, and deodorizing properties. To develop multifunctional textiles with deodorization, UV protection, and good thermal and mechanical properties, this study utilized a compounding method to modify citric acid-pre-treated cotton fabrics through a two-dipping and two-padding process using a blend finishing solution of silk sericin protein and nano-titanium dioxide. Observations of the microstructure before and after fabric finishing, along with evaluations of deodorization, UV protection, and thermal properties, revealed that controlling the proportion of the silk sericin protein/nano-titanium dioxide blend finishing solution can result in a smooth surface of the modified cotton fabric. This modification not only enhances the fabric’s UV protection and tensile strength but also improves its thermal properties while imparting certain deodorization capabilities. Comprehensive analysis concludes that using silk sericin protein and nano-titanium dioxide for modifying cotton fabric to prepare multifunctional textiles with deodorization, UV protection, and good thermal and mechanical performance is feasibly viable.

Liquid fertilizers produced by microwave-assisted acid hydrolysis of livestock and poultry wastes and their effects on hot pepper cultivation.

Liquid fertilizers (LFs) produced by microwave-assisted acid hydrolysis of livestock and poultry wastes were applied to potted hot pepper (Capsicum annuum L.) to evaluate their potential to be used as amino acid LFs. A preliminary experiment was conducted to determine the optimum acid-hydrolysis conditions for producing LFs from a mixture of pig hair and faeces (P) and another mixture of chicken feathers and faeces (C). Two LFs were produced under the optimum acid-hydrolysis conditions (acidification by sulphuric acid (7.5 mol L-1) in a microwave (200 W) for 90 minutes), and a commercial amino acid LF (Guo Guang (GG)) was used for comparison. P, C and GG fertilizers were tested in potted hot pepper cultivation at two doses, whereas no fertilizer application served as the control (CK). P and C fertilizers significantly increased the fruit yield compared with GG fertilizer, particularly at the higher dose. Moreover, the treatments improved the fruit vitamin C and soluble sugar contents in the order of C > P > GG compared with CK. These results could be attributed to more types of amino acids in C fertilizer than in P and GG fertilizers. The results also indicated that the prepared fertilizers could significantly increase the shoot and root dry weight, soil available nitrogen and phosphorus contents and nitrogen, phosphorus, and potassium (NPK) uptake by plants compared with CK. In conclusion, microwave-assisted acid hydrolysis could effectively convert unusable wastes into valuable fertilizers comparable or even superior to commercial fertilizers.

Biomechanically tunable scaffolds for bone tissue regeneration and testbeds of cancer bone metastasis

Current challenges in bone regeneration and design of humanoid 3D bone metastases cancer testbeds can be overcome by designing bone-mimetic tissue engineering scaffolds with tunable mechanical and biological properties. This study employs three unnatural amino acids to modify montmorillonite clay (MMT), producing polymer clay nanocomposites (PCNs) to construct 3D bone-mimetic scaffolds. The modification of MMT clay with 5-aminovaleric acid, (±)-2-aminopimelic acid, and 4-(4-Aminophenyl) butyric acid is analyzed through x-ray diffraction (XRD) and fourier-transform infrared spectroscopy (FTIR), revealing changes in the interlayer spacing and functional groups. Molecular modeling elucidates the interaction energies in the amino acid intercalated nanoclays that influence the mechanical properties of the scaffolds. 4-(4-Aminophenyl) butyric acid-modified scaffolds exhibited the highest compressive strength, highlighting the critical influence of molecular interactions on the mechanical properties of the PCN. Despite being a small fraction of the scaffold, the presence and type of amino acids significantly affect the scaffold mechanical properties. Cell viability assays affirm biocompatibility of scaffolds. The amino acids within the nanoclays also impact mineralization on scaffolds seeded with human mesenchymal stem cells (hMSCs). Amino acid type also influences the amount of mineralization in the scaffolds. A sequential culture involving hMSCs and breast cancer cells (MCF-7) on the scaffold mimics breast cancer metastasis to bone. Enhanced mineralization by bone cells in the presence of MCF-7 cells is observed, emphasizing their osteoblastic characteristics. Hence, 3D scaffolds for bone regeneration and bone metastasis cancer testbeds can exhibit tunable mechanical properties and biological responses though a simulation guided choice of unnatural amino acids.

Pyrene and its derivatives increase lung adverse effects by activating aryl hydrocarbon receptor transcription

Derivatives of polycyclic aromatic hydrocarbons (PAHs) pose significant threat to environment and human health due to their widespread and potential hazards. However, adverse effects and action mechanisms of PAH derivatives on human health have not been attempted yet. Herein, we chose pyrene and its derivatives (1-hydroxypyrene, 1-nitropyrene, and 1-methylpyrene) to investigate adverse effect mechanism to human lungs using in vitro and in vivo methods. Results showed that pyrene derivatives have higher lung health risks than original pyrene. They can activate AhR, subsequently affecting expression of downstream target genes CYP1A1 and CYP1B1. The binding energies of pyrene and its derivatives ranged from −16.07 to −27.25 kcal/mol by molecular dynamics simulations, implying that pyrene and its derivatives acted as agonists of AhR and increased adverse effects on lungs. Specifically, 1-nitropyrene exhibited stabler binding conformation and stronger AhR expression. In addition, sensitivity of pyrene and its derivatives to AhR activation was attributed to type and number of key amino acids in AhR, that is, pyrene (Leu293), 1-nitropyrene (Cys333, Met348, and Val381), 1-hydroxypyrene (Leu293 and Phe287), and 1-methylpyrene (Met348). In summary, we provide a universal approach for understanding action mechanisms of PAH derivatives on human health, and their adverse effects should be taken seriously.

Application of a modern theoretical approach to the study of the interaction of KR-12 peptides derived from human cathelicidins with Cu(II) ions.

The human cationic antimicrobial protein (hCAP) corresponding to the overlapping sequences of 151-162 of hCAP named KR-12 peptide is the smallest portion of the only type of human Cathelicidin, which has been shown to be modifiable into a more effective antimicrobial. In this study, an in silico analysis, supported by potentiometric titration and isothermal titration calorimetry techniques, was performed to identify potential Cu(II) binding sites of KR-12. The analysis of the presented data at the given theoretical level (GFN2-xTB/ALPB) revealed which peptide chain fragments are involved in the most favourable KR-12-Cu(II) binding mode. Based on a quantum chemical approach, the most favourable coordination modes of Cu(II) to peptides are proposed together with the discussion of the chemical nature of the interactions. The presented results demonstrated that KR-12 interacts with metal ions mostly via the main chain's oxygen atoms; however, the two types of amino acids that are expected to be vital for the interaction of Cu(II) are D (aspartic acid) and R29 (arginine). It was demonstrated that in order to explain the complexity of the interaction process in peptide-metal ion systems, the use of theoretical methods is sometimes necessary to explain the details of the experimental results and provide an in-depth understanding of these dynamic systems.

Phytochemistry of Red Ginseng, a Steam-Processed Panax ginseng.

Asian ginseng, the root of Panax ginseng C.A.Meyer, occupies a prominent position in the list of best-selling natural products in the world. There are two major types of ginseng roots: white ginseng and red ginseng, each with numerous preparations. White ginseng is prepared by air-drying fresh Asian ginseng roots after harvest. Red ginseng is prepared by steaming roots in controlled conditions using fresh or raw Asian ginseng. Red ginseng is commonly used in Asian countries due to its unique chemical profile, different therapeutic efficacy, and increased stability. Compared with the widespread research on white ginseng, the study of red ginseng is relatively limited. In this paper, after a botanical feature description, the structures of different types of constituents in red ginseng are systematically described, including naturally occurring compounds and those resulting from the steam processing. In red ginseng phytochemical studies, the number of published reports on ginsenosides is significantly higher than that for other constituents. Up to now, 57 ginsenosides have been isolated and characterized in red ginseng. The structural transformation pathways during steaming have been summarized. In comparison with white ginseng, red ginseng also contains other constituents, including polyacetylenes, Maillard reaction products, other types of glycosides, lignans, amino acids, fatty acids, and polysaccharides, which have also been presented. Appropriate analytical methods are necessary for differentiating between unprocessed white ginseng and processed red ginseng. Specific marker compounds and chemical profiles have been used to discriminate red ginseng from white ginseng and adulterated commercial products. Additionally, a brief phytochemical profile comparison has been made between white ginseng and black ginseng, and the latter is another type of processed ginseng prepared from white or red ginseng by steaming several times. In conclusion, to ensure the safe and effective use of red ginseng, phytochemical and analytical studies of its constituents are necessary and even crucial.

Detection and prebiotic chemistry of possible glycine precursor molecule methylenimine towards the hot molecular core G10.47+0.03

Abstract Amino acids are essential for the synthesis of protein. Amino acids contain both amine (R–NH2) and carboxylic acid (R–COOH) functional groups, which help to understand the possible formation mechanism of life in the universe. Among the 20 types of amino acids, glycine (NH2CH2COOH) is known as the simplest non-essential amino acid. In the last 40 years, all surveys of NH2CH2COOH in the interstellar medium, especially in the star-formation regions, have failed at the millimetre and sub-millimetre wavelengths. We aimed to identify the possible precursors of NH2CH2COOH, because it is highly challenging to identify NH2CH2COOH in the interstellar medium. Many laboratory experiments have suggested that methylenimine (CH2NH) plays a key role as a possible precursor of NH2CH2COOH in the star-formation regions via the Strecker synthesis reaction. After spectral analysis using the local thermodynamic equilibrium (LTE) model, we successfully identified the rotational emission lines of CH2NH towards the hot molecular core G10.47+0.03 using the Atacama Compact Array (ACA). The estimated column density of CH2NH towards G10.47+0.03 is (3.40 ± 0.2) × 1015 cm−2 with a rotational temperature of 218.70 ± 20 K, which is estimated from the rotational diagram. The fractional abundance of CH2NH with respect to H2 towards G10.47+0.03 is 2.61 × 10−8. We found that the derived abundance of CH2NH agree fairly well with the existing two-phase warm-up chemical modelling abundance value of CH2NH. We discuss the possible formation pathways of CH2NH within the context of hot molecular cores, and we find that CH2NH is likely mainly formed via neutral–neutral gas-phase reactions of CH3 and NH radicals towards G10.47+0.03.

Carbon Dioxide Capture Using Ionic Liquids Containing Amino Acid-Type Anions. Effect of the Cation, Anion on the Absorption Efficiency

Abstract. In this work, the synthesis of twelve ionic liquids (ILs) with imidazolium cation and amino acid-derived anions and their evaluation as carbon dioxide (CO2) absorbents both, in pure form and aqueous solution (30 % of water) are reported and compared with monoetanolamine (MEA), which is a well-known commercial absorbent with wide application in the Petroleum Industry for capturing acid gases. The effect of both cation substituent features such as length and unsaturation of alkyl chains and amino acid structure at the anion on the CO2 absorption efficiency was studied. All the ILs displayed good CO2 absorption efficiency, being the ILs derived from 1-octyl-3-vinylimidazolium the most effective for this purpose, especially with lysinate anion ([OVI][L]); a capture rate of 1501 mg CO2/mol of IL was achieved when it was diluted in water (30 %). Resumen. En este trabajo se reporta la síntesis de doce líquidos iónicos (LIs) con el catión imidazolio y los aniones derivados de aminoácidos y la evaluación de estos compuestos como absorbentes de dióxido de carbono (CO2), tanto empleando los absorbentes puros, como en solución acuosa (30 % de agua). Los resultados se comparan con los obtenidos con monoetanolamina (MEA), que es un conocido absorbente comercial con amplia aplicación en la Industria del Petróleo en la captura de gases ácidos. Se estudió el efecto de las características de ambos N-sustituyentes de los cationes, como la longitud y la presencia de insaturación en las cadenas de alquilo y la estructura de aminoácidos que conforman los aniones de los LIs estudiados, en la eficiencia de absorción de CO2. Todos los LIs mostraron una buena eficiencia de absorción de CO2, siendo los LIs derivados del 1-octil-3-vinilimidazolio los más efectivos para este fin, especialmente con el anión lisinato ([OVI][L]); se logró una tasa de captura de 1501 mg CO2/mol de LIs cuando el absorbente se diluyó en agua (30 %).

Effect of the type of amino acid on the biodegradation of ibuprofen derivatives

Effect of the type of amino acid on the biodegradation of ibuprofen derivatives