|别名||L-2-氨基丁酸;L-α-Aminobutyric acid L(+)-2-Aminobutyric acid (S)-(+)-2-Aminobutyric acid 2-Aminobutanoic acid H-Abu-OH|
|个人防护设备||dust mask type N95 (US),Eyeshields,Faceshields,Gloves|
Previous work by others have suggested the occurrence of one or more chemical or metabolic 'markers' for ME/CFS including specific amino acids and organic acids and a number of unidentified ...Read More
L-Carnitine has important roles in intermediary metabolism and patients with end-stage renal disease who are undergoing hemodialysis may develop a secondary L-carnitine deficiency. The extent of accum...Read More
Improving the serum D-xylose test for the identification of patients with small intestinal malabsorption.
D-Xylose absorption testing is a simple, low-cost method of screening for small intestinal malabsorption. The optimum method to measure D-xylose absorption (serum vs. urine testing) is uncertain....Read More
Accumulation of trimethylamine and trimethylamine-N-oxide in end-stage renal disease patients undergoing haemodialysis.
Trimethylamine (TMA) is a short-chain tertiary aliphatic amine that is derived from the diet either directly from the consumption of foods high in TMA or by the intake of food high in precursors to TM...Read More
Nitric oxide synthase requires tetrahydrobiopterin for its activity. In animal models of sepsis, changes in circulating tetrahydrobiopterin concentrations precede increases in nitrate. We measured pla...Read More
Serum concentrations of asymmetric (ADMA) and symmetric (SDMA) dimethylarginine in patients with chronic kidney diseases.
NO synthesis is inhibited by the dimethylarginine (DMA) ADMA, which accumulates, similar to SDMA, in the plasma of patients suffering from chronic renal failure (CRF). ADMA and possibly SDMA contribut...Read More
Pteridine metabolism is impaired in the uraemic state. This may affect cardiovascular function and contribute to malnutrition. We wished to clarify further the impact of impaired pteridine metabolism....Read More
Increased plasma phenylacetic acid in patients with end-stage renal failure inhibits iNOS expression.
NO prevents atherogenesis and inflammation in vessel walls by inhibition of cell proliferation and cytokine-induced endothelial expression of adhesion molecules and proinflammatory cytokines. Reduced ...Read More
Effects of oral administration of zinc and diiodohydroxyquinolein on plasma zinc levels of uremic patients.
Patients with chronic renal failure often have low plasma zinc (Zn) levels. Some factors that may account for abnormal Zn metabolism in these patients are low dietary Zn intake, a specific Zn transpor...Read More
Determination of polyamines in hydrolysates of uremic plasma by high-performance cation-exchange column chromatography.
The levels of putrescine, cadaverine, spermidine and spermine in uremic plasma were determined with an automatic polyamine analyzer with a 7.5 X 0.2 cm I.D. cation-exchange column using a stepwise sod...Read More
Advanced glycation end products (AGEs), e.g., carboxymethyllysine (CML) or imidazolone are involved in several age-related disorders. Concerning their accumulation, the importance of hepatic and renal...Read More
Plasma histamine concentrations were measured using a commercially available monoclonal antibody radioimmunoassay in 38 patients with nephrotic syndrome, end stage renal failure, those receiving haemo...Read More
Myeloperoxidase (MPO), which is secreted during activation of neutrophils, may serve as one mechanistic link among persistent inflammation, oxidative stress, and cardiovascular disease. This study rel...Read More
Hyperhomocysteinemia is a risk factor for atherosclerosis that is common in chronic renal failure (CRF), but its cause is unknown. Homocysteine metabolism is linked to betaine-homocysteine methyl tran...Read More
The purpose of this study was to examine the effect of nocturnal hemodialysis (NHD) on serum amino acid (AA) profile....Read More
The presence of mixed disaccharides (maltose and isomaltose) in plasma from uremic patients has been previously investigated using gel-permeation chromatography. However, this method is unable to sepa...Read More
Plasma free amino acids and their metabolites in Taiwanese patients on hemodialysis and continuous ambulatory peritoneal dialysis.
The high prevalence of protein-energy malnutrition is a critical issue for patients with end stage renal disease (ESRD) on hemodialysis (HD) or continuous ambulatory peritoneal dialysis (CAPD). Levels...Read More
Differential 12C-/13C-isotope dansylation labeling and fast liquid chromatography/mass spectrometry for absolute and relative quantification of the metabolome.
We report a new quantitative metabolome profiling technique based on differential (12)C-/(13)C-isotope dansylation labeling of metabolites, fast liquid chromatography (LC) separation and electrospray ...Read More
Three-dimensional quantitative structure-activity relationship analyses of substrates of the human proton-coupled amino acid transporter 1 (hPAT1).
The proton-coupled amino acid transporter hPAT1 has recently gained much interest due to its ability to transport small drugs thereby allowing their oral administration. A three-dimensional quantitati...Read More
Engineering of a novel biochemical pathway for the biosynthesis of L-2-aminobutyric acid in Escherichia coli K12.
L-2-Aminobutyric acid was synthesised in a transamination reaction from L-threonine and L-aspartic acid as substrates in a whole cell biotransformation using recombinant Escherichia coli K12. The cell...Read More
CytC3, a member of the recently discovered class of nonheme Fe(II) and alpha-ketoglutarate (alphaKG)-dependent halogenases, catalyzes the double chlorination of L-2-aminobutyric acid (Aba) to produce ...Read More
Asymmetric synthesis of an unnatural amino acid was demonstrated by omega-transaminase from Vibrio fluvialis JS17. L-2-Aminobutyric acid was synthesized from 2-oxobutyric acid and benzylamine with an ...Read More
The crystal structure of L-2-aminobutyric acid, an L-alanine analogue with an ethyl rather than a methyl side chain, has proved elusive owing to problems growing diffraction quality crystals. Good dif...Read More
The introduction of non-natural modules could provide unprecedented control over folding/unfolding behavior, conformational stability, and biological function of proteins. Success requires the interro...Read More
The crystal structure of the PNA (peptide nucleic acid) oligomer H-Lys-HalG-AlaG-HalC-AlaG-HalC-AlaC-Lys-NH(2) (PNA1, amino acids with D-configuration are underlined, Ala = alanyl, Hal = homoalanyl) h...Read More
Synaptic remodelling coordinated with dendritic growth is essential for proper development of neural connections. After establishment of synaptic contacts, synaptic junctions are thought to become sta...Read More
A deracemization method was developed to generate optically pure L-homoalanine from racemic homoalanine using D-amino acid oxidase and ω-transaminase. A whole cell reaction using a biphasic system co...Read More
Site-selective traceless Staudinger ligation for glycoprotein synthesis reveals scope and limitations.
We're sorry this abstract is currently not available....Read More
Correlation between symmetry breaker position and the preferences of conformationally constrained homopeptides: a molecular dynamics investigation.
The conformational tendencies of C(alpha,alpha)-diethylglycine (Deg)-based peptides have been studied in solution using all atom molecular dynamics simulations. Specifically, the conformational effect...Read More
Our aim was to determine changes in free amino acid (FAA) and dipeptide (DP) concentrations in probable Alzheimer's disease (pAD) subjects compared with control (CT) subjects using liquid chromat...Read More
Ratio of 8-hydroxyguanine in intact DNA to free 8-hydroxyguanine is increased in Alzheimer disease ventricular cerebrospinal fluid.
Markers of oxidative stress are increased in cerebrospinal fluid (CSF) of patients with Alzheimer disease (AD), although none of those reported are appropriate diagnostic markers because of the overla...Read More
The effect of increased concentrations of homocysteine on the concentration of (E)-4-hydroxy-2-nonenal in the plasma and cerebrospinal fluid of patients with Alzheimer's disease.
There is evidence that increased blood concentrations of homocysteine may be a risk factor for Alzheimer's disease. (E)-4-hydroxy-2-nonenal (HNE) is a neurotoxic product of lipid peroxidation tha...Read More
Thiamine is an essential cofactor for several important enzymes involved in brain oxidative metabolism, such as the alpha-ketoglutarate dehydrogenase complex (KGDHC), pyruvate-dehydrogenase complex (P...Read More
Remarkable increase in the concentration of 8-hydroxyguanosine in cerebrospinal fluid from patients with Alzheimer's disease.
To investigate the possible role of oxidative RNA damage in the pathogenesis of Alzheimer's disease (AD), the concentrations of the oxidative stress marker 8-hydroxyguanosine (8-OHG) were measure...Read More
Increasing evidence suggests an interaction of oxidative stress and the formation of advanced glycation end products (AGE) in the onset and progression of Alzheimer's disease. We studied levels o...Read More
Induced-fit in the gas phase: conformational effects on the enantioselectivity of chiral tetra-amide macrocycles.
The structure, stability, and reactivity of proton-bound diastereomeric [M x H x A]+ complexes between some amino acid derivatives (A) and several chiral tetra-amide macrocycles (M) have been investig...Read More
Preparation of optically active 2-aminobutanoic acid via optical resolution by replacing crystallization.
An attempt was made to use a simple procedure to obtain (R)- and (S)-2-aminobutanoic acids [(R)- and (S)-1] which are non-proteinogenic alpha-amino acids and are useful as chiral reagents in asymmetri...Read More
Staphylococcus epidermidis isolated from spoiled frozen marine fish samples exhibited optimum lipase activity of 8.1 U within 72 h in batch fermentation. Inducible effect of different sugars, nitrogen...Read More
PchC thioesterase optimizes nonribosomal biosynthesis of the peptide siderophore pyochelin in Pseudomonas aeruginosa.
In Pseudomonas aeruginosa, the antibiotic dihydroaeruginoate (Dha) and the siderophore pyochelin are produced from salicylate and cysteine by a thiotemplate mechanism involving the peptide synthetases...Read More
Comparative effects of GLP-1 and GIP on cAMP production, insulin secretion, and in vivo antidiabetic actions following substitution of Ala^8/Ala^2 with 2-aminobutyric acid
The two major incretin hormones, glucagon-like peptide-1 (GLP-1), and glucose-dependent insulinotropic polypeptide (GIP), are currently being considered as prospective drug candidates for treatment of...Read More
We evaluated new (111)In-labeled amino acid derivatives, in which the amino acids are conjugated with1,4,7,10-tetra-azacyclododecane-1,4,7,10-tetraacetic acid (DOTA), 1,4,7,10-tetraazacyclododecane-1,...Read More
Removal of L-alanine from the production of L-2-aminobutyric acid by introduction of alanine racemase and D-amino acid oxidase.
L-2-Aminobutyric acid can be synthesized in a transamination reaction from L-threonine and L-aspartic acid as substrates by the action of threonine deaminase and aromatic aminotransferase, but the by-...Read More
Although abnormal hepatic methionine metabolism plays a central role in the pathogenesis of experimental alcoholic liver disease (ALD), its relationship to the risk and severity of clinical ALD is not...Read More
An increasing number of new biomarkers of alcohol abuse appear in the literature. The most commonly used biomarkers (5-hydroxytryptophol, fatty acid ethyl esters, ethyl glucuronide, phosphatidyl ethan...Read More
The dramatic increase in healthcare cost has become a significant burden to the world. Many patients are denied the accessibility of medication because of the high price of drugs. Total biosynthesis o...Read More
One carbon metabolism disturbances and the C677T MTHFR gene polymorphism in children with autism spectrum disorders.
Autism spectrum disorders (ASDs), which include the prototypic autistic disorder (AD), Asperger's syndrome (AS) and pervasive developmental disorders not otherwise specified (PDD-NOS), are comple...Read More
Conformational studies of [Abu(3, 11)]-SFTI-1, an analogue of the trypsin inhibitor isolated from sunflower seeds.
With only 14 amino acid residues, the trypsin inhibitor SFTI-1 is the smallest naturally occurring serine proteinase inhibitor. It consists of two cyclic fragments (with head-to-tail cyclization and a...Read More
The A-chain of insulin contacts the insert domain of the insulin receptor. Photo-cross-linking and mutagenesis of a diabetes-related crevice.
The contribution of the insulin A-chain to receptor binding is investigated by photo-cross-linking and nonstandard mutagenesis. Studies focus on the role of Val(A3), which projects within a crevice be...Read More
Enzymatic incorporation of a halogen atom is a common feature in the biosyntheses of more than 4,500 natural products. Halogenation of unactivated carbon centers in the biosyntheses of several compoun...Read More
Crystal structure of the ω-aminotransferase from Paracoccus denitrificans and its phylogenetic relationship with other class III aminotransferases that have biotechnological potential.
Apart from their crucial role in metabolism, pyridoxal 5'-phosphate (PLP)-dependent aminotransferases (ATs) constitute a class of enzymes with increasing application in industrial biotechnology. ...Read More
Determination of N-ethylglycine in urine of cancer patients with metastatic bone disease by HPLC using 4-(5,6-dimethoxy-2-phthalimidinyl)-2-methoxyphenylsulfonyl chloride as a fluorescent labeling reagent.
A simple and highly sensitive HPLC for the determination of N-ethylglycine in urine was developed. The labeling reaction of N-ethylglycine with 4-(5,6-dimethoxy-2-phthalimidinyl)-2-methoxyphenylsulfon...Read More
Amino acids in plasma and CSF and monoamine metabolites in CSF: interrelationship in healthy subjects.
Plasma and cerebrospinal fluid (CSF) concentrations of amino acids were measured in 65 healthy volunteers (50 men and 15 women). The CSF levels of the monoamine metabolites homovanillic acid (HVA), 3-...Read More
A pair of siblings with clinical symptoms of cyclic vomiting and ketoacidosis were found to have a biochemical triad of normoglycemia, ketoacidosis and elevated levels of alpha-hydroxy- and alpha-amin...Read More
To study changes in amino acid metabolism and biogenic amines in Parkinson's disease, we set up a prospective study and measured biogenic amines, their main metabolites, and 22 different amino ac...Read More
Glutamate-cysteine ligase (GLCL) catalyzes the rate-limiting step in glutathione biosynthesis. GLCL comprises regulatory (GLCLR) and catalytic (GLCLC) subunits. To understand better the structure-func...Read More
Exogenous @c-glutamyl cycle compounds supplemented to in vitro maturation medium influence in vitro fertilization, culture, and viability parameters of porcine oocytes and embryos
High concentrations of intracellular glutathione (GSH) enhance in vitro production of porcine embryos. Objectives were: (1) to determine the effects of @c-glutamyl cycle compound supplements to the IV...Read More
The haematic concentration of 26 metals and the oxidative damage in 60 patients (20 males and 40 females) affected by Alzheimer's disease and 44 healthy individuals (33 males and 11 females) were...Read More
Patterns of cerebrospinal fluid catechols support increased central noradrenergic responsiveness in aging and Alzheimer's disease.
High cerebrospinal fluid (CSF) norepinephrine (NE) concentrations in aging and Alzheimer's disease (AD) could reflect decreased NE clearance from central nervous system (CNS) extracellular fluid ...Read More
Differential acetylcholine and choline concentrations in the cerebrospinal fluid of patients with Alzheimer's disease and vascular dementia.
An important aspect of Alzheimer's disease (AD) is loss or impairment of cholinergic neurons. It is controversial whether there is a similar cholinergic impairment and cerebral deficit of acetylc...Read More
Previous studies suggest the presence of increased concentrations of cerebral myo-inositol in Alzheimer disease (AD). To characterize this abnormality further, we quantified myo-inositol and several o...Read More
The cobalamin status was evaluated in Alzheimer dementia (n = 26), other dementias (n = 24), various gerontopsychiatric disorders (n = 25), and in neuro-psychiatrically healthy controls (n = 20). Supp...Read More
Experimental and clinical studies give evidence for breakdown of membrane phospholipids during neurodegeneration. In the present study, we measured the levels of glycerophosphocholine (GPCh), phosphoc...Read More
Plasma amino acid levels with a note on membrane transport: characteristics, regulation, and metabolic significance.
The plasma concentration of an amino acid (AA) is the result of its rates of appearance (Ra) in and disappearance (Rd) from plasma. As for most nutrients, AA Ra and Rd are tightly regulated and at the...Read More
24S-Hydroxycholesterol (24OHC) and 27-hydroxycholesterol (27OHC) are two structurally similar oxysterols of different origins--the former almost exclusively formed in the brain and the latter formed t...Read More
The chemisorptive enantioselectivity of propylene oxide is examined on Pd(111) surfaces templated by chiral 2-methylbutanoate and 2-aminobutanoate species. It has been found previously that chiral pro...Read More