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Free form amino acids

M P Swetha, S P Muthukumar
Ridge gourd (Luffa acutangula) is consumed as a vegetable after peeling off the skin which is a domestic waste. Luffa acutangula peel (LAP) was observed to be a good source of fiber (20.6 %) and minerals (7.7 %). Amino acid analysis revealed presence of the highest content of Carnosine followed by aspartic acid and aminoadipic acid. Antioxidant activity of different extracts showed that ethyl acetate extract was more potent when compared to other solvent extractions. It exhibited a significant amount of phenolic acids like p-coumaric acid (68...
July 2016: Journal of Food Science and Technology
P D Austin, K S Hand, M Elia
BACKGROUND: As lipid in parenteral nutrition (PN) purportedly enhances microbial growth, recommendations limit infusion of lipid PN (or lipid emulsion) from a single container to 24h (48h for lipid-free PN). However, the associated evidence base is ambiguous. AIM: To examine factors affecting microbial growth in PN. METHODS: A systematic review with meta-analyses examined effects of nutrients on microbial growth in PN infusates over a 48-h period using the growth ratio {GR=log10[colony-forming units (cfu)/mL at 48h/cfu/mL at time zero]}...
September 7, 2016: Journal of Hospital Infection
Christoph T Schanzenbächer, Sivakumar Sambandan, Julian D Langer, Erin M Schuman
Homeostatic scaling adjusts the strength of synaptic connections up or down in response to large changes in input. To identify the landscape of proteomic changes that contribute to opposing forms of homeostatic plasticity, we examined the plasticity-induced changes in the newly synthesized proteome. Cultured rat hippocampal neurons underwent homeostatic up-scaling or down-scaling. We used BONCAT (bio-orthogonal non-canonical amino acid tagging) to metabolically label, capture, and identify newly synthesized proteins, detecting and analyzing 5,940 newly synthesized proteins using mass spectrometry and label-free quantitation...
October 19, 2016: Neuron
Vitthal B Saptal, Bhalchandra M Bhanage
A series of highly efficient, bifunctional ionic liquids containing a quaternary alkyl ammonium cation and an amine anion were prepared from choline and amino acids, respectively. Nine ILs were synthesized, characterized, and applied as organocatalysts for the chemical fixation of carbon dioxide to form cyclic carbonates and quinazoline-2,4(1 H,3 H)-diones. A binary mixture of an IL and a co-catalysts generates deep eutectic solvents (DESs) and accelerates the rate of the cycloaddition reaction at atmospheric pressure and low temperature (70 °C)...
October 20, 2016: ChemSusChem
Isabel M López-Lara, Otto Geiger
The glycerophospholipids phosphatidylethanolamine, phosphatidylglycerol (PG), and cardiolipin (CL) are major structural components of bacterial membranes. In some bacteria, phosphatidylcholine or phosphatidylinositol and its derivatives form part of the membrane. PG or CL can be modified with the amino acid residues lysine, alanine, or arginine. Diacylglycerol is the lipid anchor from which syntheses of phosphorus-free glycerolipids, such as glycolipids, sulfolipids, or homoserine-derived lipids initiate. Many membrane lipids are subject to turnover and some of them are recycled...
October 17, 2016: Biochimica et Biophysica Acta
Ekaterina Darii, Sandra Alves, Yves Gimbert, Alain Perret, Jean-Claude Tabet
Non-covalent complexes (NCC) between hexose monophosphates (HexP) and arginine (R) were analyzed using ESI MS and MS/MS in negative mode under different (hard, HC and soft, SC) desolvation conditions. High resolution mass spectrometry (HRMS) revealed the presence of different ionic species, namely, homo- and heteromultimers of R and HexP. Deprotonated heterodimers and corresponding sodiated species were enhanced under HC likely due to a decrease in available charge number associated with the reduction of H(+)/Na(+) exchange...
September 26, 2016: Journal of Chromatography. B, Analytical Technologies in the Biomedical and Life Sciences
Siegfried Zerche, Klaus-Thomas Haensch, Uwe Druege, Mohammad-Reza Hajirezaei
BACKGROUND: Adventitious root (AR) formation in axillary shoot tip cuttings is a crucial physiological process for ornamental propagation that is utilised in global production chains for young plants. In this process, the nitrogen and carbohydrate metabolisms of a cutting are regulated by its total nitrogen content (Nt), dark exposure during transport and irradiance levels at distinct production sites and phases through a specific plasticity to readjust metabolite pools. Here, we examined how elevated Nt contents with a combined dark exposure of cuttings influence their internal N-pools including free amino acids and considered early anatomic events of AR formation as well as further root development in Petunia hybrida cuttings...
October 10, 2016: BMC Plant Biology
I R Sasselli, C G Pappas, E Matthews, T Wang, N T Hunt, R V Ulijn, T Tuttle
Despite progress, a fundamental understanding of the relationships between the molecular structure and self-assembly configuration of Fmoc-dipeptides is still in its infancy. In this work, we provide a combined experimental and computational approach that makes use of free energy equilibration of a number of related Fmoc-dipeptides to arrive at an atomistic model of Fmoc-threonine-phenylalanine-amide (Fmoc-TF-NH2) which forms twisted fibres. By using dynamic peptide libraries where closely related dipeptide sequences are dynamically exchanged to eventually favour the formation of the thermodynamically most stable configuration, the relative importance of C-terminus modifications (amide versus methyl ester) and contributions of aliphatic versus aromatic amino acids (phenylalanine F vs...
October 12, 2016: Soft Matter
Dongli Guan, Zhilei Chen
Proteins purified using affinity-based chromatography often exploit a recombinant affinity tag. Existing methods for the removal of the extraneous tag, needed for many applications, suffer from poor efficiency and/or high cost. Here we describe a simple, efficient, and potentially low-cost approach-split intein-mediated ultrarapid purification (SIRP)-for both the purification of the desired tagged protein from Escherichia coli lysate and removal of the tag in less than 1 h. The N- and C-fragment of a self-cleaving variant of a naturally split DnaE intein from Nostoc punctiforme are genetically fused to the N-terminus of an affinity tag and a protein of interest (POI), respectively...
2017: Methods in Molecular Biology
Joseph R Gord, Daniel M Hewett, Alicia O Hernandez-Castillo, Karl N Blodgett, Matthew C Rotondaro, Adalgisa Varuolo, Matthew A Kubasik, Timothy S Zwier
The conformational preferences of a series of capped peptides containing the helicogenic amino acid aminoisobutyric acid (Aib) (Z-Aib-OH, Z-(Aib)2-OMe, and Z-(Aib)4-OMe) are studied in the gas phase under expansion-cooled conditions. Aib oligomers are known to form 310-helical secondary structures in solution and in the solid phase. However, in the gas phase, accumulation of a macrodipole as the helix grows could inhibit helix stabilization. Implementing single-conformation IR spectroscopy in the NH stretch region, Z-Aib-OH and Z-(Aib)2-OMe are both observed to have minor conformations that exhibit dihedral angles consistent with the 310-helical portion of the Ramachandran map (ϕ, ψ = -57°, -30°), even though they lack sufficient backbone length to form 10-membered rings which are a hallmark of the developed 310-helix...
September 14, 2016: Physical Chemistry Chemical Physics: PCCP
Alireza Farasat, Fatemeh Rahbarizadeh, Ghader Hosseinzadeh, Sharareh Sajjadi, Mehdi Kamali, Amir Homayoun Keihan
Epidermal growth factor receptor (EGFR), a transmembrane glycoprotein, is overexpressed in many cancers such as head-neck, breast, prostate, and skin cancers for this reason it is a good target in cancer therapy and diagnosis. In nanobody-based cancer diagnosis and treatment, nanobodies with high affinity toward receptor (e.g. EGFR) results in effective treatment or diagnosis of cancer. In this regard, the main aim of this study is to develop a method based on molecular dynamic (MD) simulations for designing of 7D12 based nanobody with high affinity compared with wild-type nanobody...
October 3, 2016: Journal of Biomolecular Structure & Dynamics
Corinna Krempl, Hanna M Heidel-Fischer, Guillermo Hugo Jiménez-Alemán, Michael Reichelt, Riya Christina Menezes, Wilhelm Boland, Heiko Vogel, David G Heckel, Nicole Joußen
Gossypol is a polyphenolic secondary metabolite produced by cotton plants, which is toxic to many organisms. Gossypol's aldehyde groups are especially reactive, forming Schiff bases with amino acids of proteins and cross-linking them, inhibiting enzyme activities and contributing to toxicity. Very little is known about gossypol's mode of action and its detoxification in cotton-feeding insects that can tolerate certain concentrations of this compound. Here, we tested the toxicity of gossypol and a gossypol derivative lacking free aldehyde groups (SB-gossypol) toward Helicoverpa armigera and Heliothis virescens, two important pests on cotton plants...
September 26, 2016: Insect Biochemistry and Molecular Biology
Yajie Wang, Pengyao Xing, Shangyang Li, Mingfang Ma, Minmin Yang, Yimeng Zhang, Bo Wang, Aiyou Hao
This paper reports an interesting type of self-assembly systems based on dynamic covalent bonds. The systems are pH-responsible and reversible, which could be utilized for controlling the morphology transformation of the assemblies. In alkaline conditions, the amine group of 11-aminoundecanoic acid (AUA) can connect with the aldehyde group of benzaldehyde (BA) or 1-naphthaledhyde (NA) by dynamic covalent bond to form a small organic building block accompanied by the morphological transformation from vesicles to fibers...
October 7, 2016: Langmuir: the ACS Journal of Surfaces and Colloids
V Y Brodsky, L A Malchenko, D S Konchenko, N D Zvezdina, T K Dubovaya
Primary cultures of rat hepatocytes were studied in serum-free media. Ultradian protein synthesis rhythm was used as a marker of cell synchronization in the population. Addition of glutamic acid (0.2 mg/ml) to the medium of nonsynchronous sparse cultures resulted in detection of a common protein synthesis rhythm, hence in synchronization of the cells. The antagonist of glutamic acid metabotropic receptors MCPG (0.01 mg/ml) added together with glutamic acid abolished the synchronization effect; in sparse cultures, no rhythm was detected...
August 2016: Biochemistry. Biokhimii︠a︡
Mengmeng Zhang, Hong Zhang, Huixian Li, Furao Lai, Xiaofeng Li, Yuqian Tang, Tian Min, Hui Wu
Betaine (BET) is a native compound widely studied as an antioxidant in agriculture and human health. However, the antioxidant mechanism of BET remains unclear. In this research, radical scavenging assays showed that BET had little free radical scavenging activity. However, the antioxidant activity of BET was confirmed by cellular antioxidant activity (CAA) and erythrocyte hemolysis assays. The results of quantitative PCR (qPCR) and enzyme activity determination kits showed that the antioxidant activity of BET was not due to the gene expression and activity of antioxidases...
October 12, 2016: Journal of Agricultural and Food Chemistry
Aswathy N Muttathukattil, Govardhan Reddy
Understanding the role of naturally occurring protective osmolytes, such as trimethylamine N-oxide (TMAO), in the growth of amyloid fibrils implicated in neurodegenerative diseases is important to prevent fibril growth. The effect of TMAO on the growth of amyloid fibrils formed by the Sup35 prion peptide NNQQNY is studied using molecular dynamics simulations. The free-energy surface for the growth of the protofibril shows three major basins, corresponding to the free state where the peptide is in solution, the docked state where the peptide in solution interacts with the surface of the protofibril, and the locked state where the peptide is tightly bound to the protofibril, becoming a part of the fibril...
October 17, 2016: Journal of Physical Chemistry. B
Rochelle Ford, Susan J Quinn, Robert D O'Neill
Amperometric l-glutamate (Glu) biosensors, based on both wild-type and a recombinant form of l-glutamate oxidase (GluOx), were designed and characterized in terms of enzyme-kinetic, sensitivity and stability parameters in attempts to fabricate a real-time Glu monitoring device suitable for future long-term detection of this amino acid in biological and other complex media. A comparison of the enzyme from these two sources showed that they were similar in terms of biosensor performance. Optimization of the loading of the polycationic stabilization agent, polyethyleneimine (PEI), was established before investigating a range of crosslinking agents under different conditions: glutaraldehyde (GA), polyethylene glycol (PEG), and polyethylene glycol diglycidyl ether (PEGDE)...
2016: Sensors
Saheem Ahmad, Mohammed Farhan
Non-enzymatic protein glycosylation is the addition of free carbonyls to the free amino groups of proteins, amino acids, lipoproteins and nucleic acids resulting in the formation of early glycation products. The early glycation products are also known as Maillard reaction which undergoes dehydration, cyclization and rearrangement to form advanced glycation end-products (AGEs). By and large the researchers in the past have also established that glycation and the AGEs are responsible for most type of metabolic disorders, including diabetes mellitus, cancer, neurological disorders and aging...
2016: Advances in Neurobiology
Bogdan S Melnik, Galina S Nagibina, Anatoly S Glukhov, Tatiana N Melnik, Vladimir N Uversky
Various effects of amino acid substitutions on properties of globular proteins have been described in a large number of research papers. Nevertheless, no definite "rule" has been formulated as of yet that could be used by experimentalists to introduce desirable changes in the properties of proteins. Herein we attempt to establish such a "rule". To this end, a hypothesis is proposed on the effects of substitutions of hydrophobic residues with large number of contacts on free energies of different states of a globular protein...
September 14, 2016: Biochimica et Biophysica Acta
Massimiliano Peana, Serenella Medici, Heather A Pangburn, Thomas J Lamkin, Malgorzata Ostrowska, Elzbieta Gumienna-Kontecka, Maria Antonietta Zoroddu
A decapeptide, DEHGTAVMLK (DP1), and its random scrambled version, THMVLAKGED (DP2), have been studied for their interactions with manganese. The amino acid composition of the peptides was selected to include the majority of the most prevalent amino acids present in a Deinococcus radiodurans bacterium cell-free extract that contains components capable of conferring extreme resistance to ionizing radiation. The extract appears to be rich in Mn(II) complexes which seem to be responsible for protecting proteins from Reactive Oxygen Species damage...
August 30, 2016: Journal of Inorganic Biochemistry
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