Search results for "Tryptophan"
showing 10 items of 141 documents
Modern diversification of the amino acid repertoire driven by oxygen
2017
All extant life employs the same 20 amino acids for protein biosynthesis. Studies on the number of amino acids necessary to produce a foldable and catalytically active polypeptide have shown that a basis set of 7-13 amino acids is sufficient to build major structural elements of modern proteins. Hence, the reasons for the evolutionary selection of the current 20 amino acids out of a much larger available pool have remained elusive. Here, we have analyzed the quantum chemistry of all proteinogenic and various prebiotic amino acids. We find that the energetic HOMO-LUMO gap, a correlate of chemical reactivity, becomes incrementally closer in modern amino acids, reaching the level of specialize…
The genomic sequence of Exiguobacterium chiriqhucha str. N139 reveals a species that thrives in cold waters and extreme environmental conditions
2017
We report the genome sequence of Exiguobacterium chiriqhucha str. N139, isolated from a high-altitude Andean lake. Comparative genomic analyses of the Exiguobacterium genomes available suggest that our strain belongs to the same species as the previously reported E. pavilionensis str. RW-2 and Exiguobacterium str. GIC 31. We describe this species and propose the chiriqhucha name to group them. ‘Chiri qhucha’ in Quechua means ‘cold lake’, which is a common origin of these three cosmopolitan Exiguobacteria. The 2,952,588-bp E. chiriqhucha str. N139 genome contains one chromosome and three megaplasmids. The genome analysis of the Andean strain suggests the presence of enzymes that confer E. ch…
Tryptophan-Containing Dual Neuroprotective Peptides: Prolyl Endopeptidase Inhibition and Caenorhabditis elegans Protection from β-Amyloid Peptide Tox…
2018
Neuroprotective peptides represent an attractive pharmacological strategy for the prevention or treatment of age-related diseases, for which there are currently few effective therapies. Lactoferrin (LF)-derived peptides (PKHs) and a set of six rationally-designed tryptophan (W)-containing heptapeptides (PACEIs) were characterized as prolyl endopeptidase (PEP) inhibitors, and their effect on β-amyloid peptide (Aβ) toxicity in a Caenorhabditis elegans model of Alzheimer’s disease (AD) was evaluated. Two LF-derived sequences, PKH8 and PKH11, sharing a W at the C-terminal end, and the six PACEI heptapeptides (PACEI48L to PACEI53L) exhibited significant in vitro PEP inhibition. The inhibitory pe…
Isocratic high-performance liquid chromatographic determination of tryptophan in infant formulas.
1996
The application to infant formulas of a method for tryptophan determination by isocratic HPLC with UV detection at 254 nm, after derivatization with phenyl isothiocyanate, was studied. Protein was hydrolysed by barium hydroxide at 120 degrees C for 8 h, followed by derivatization with phenyl isothiocyanate, HPLC and UV detection at 254 nm. The optimum chromatographic conditions (pH, ionic strength of elution solvent and eluent ratio) were established. The analytical parameters (linearity, precision, accuracy of derivatization and limits of detection and quantification) were determined. The values obtained demonstrated that the method is useful for determining the tryptophan content of infan…
The TPH intron 7 A218C polymorphism and TCI dimension scores in alcohol-dependent patients: hints to nonspecific psychopathology
2004
Abstract Aims A linkage of certain alleles of the tryptophan hydroxylase (TPH) intron 7 A218C polymorphism to suicidality and antisocial behaviour has been described. The aim of our study was to find any association between dimensions of the Temperament and Character Inventory (TCI) indicating impulsivity and the TPH polymorphism alleles in unselected alcohol-dependent patients and age-matched controls. Methods We examined 159 alcohol-dependent patients and 161 controls with the TCI and genotyped them for the TPH intron 7 A218C polymorphism alleles. Results Although homozygous TPH genotypes were found more often in alcohol-dependent patients than in controls, an association between TCI dime…
Recessive multiple epiphyseal dysplasia (rMED): phenotype delineation in eighteen homozygotes for DTDST mutation R279W.
2003
Multiple epiphyseal dysplasia (MED) is a generalised skeletal dysplasia that although relatively mild is associated with significant morbidity. Joint pain, joint deformity, waddling gait, and short stature are the main clinical signs and symptoms. In the past, the disorder was subdivided into the milder Ribbing type, usually with flattened epiphyses,1 and the more severe Fairbank type with round epiphyses,2 but many cases were not classifiable as clearly either type.3 MED can be caused by mutations in at least six separate genes: COMP ,4–7 collagen IX ( COL9A1 , COL9A2 , and COL9A3 ),8–13 matrilin 3 ( MATN3 ),15 and the sulphate transporter, DTDST ( DTDST/SLC26A2 ). We have previously repor…
Gender specific associations of the Trp64Arg mutation in the beta3-adrenergic receptor gene with obesity-related phenotypes in a Mediterranean popula…
2001
Abstract. Corella D, Guillen M, Portoles O, Sorli JV, Alonso V, Folch J, Saiz C (School of Medicine, University of Valencia, Valencia, Spain). Gender specific associations of the Trp64Arg mutation in the β3-adrenergic receptor gene with obesity-related phenotypes in a Mediterranean population: interaction with a common lipoprotein lipase gene variation. J Intern Med 2001; 250: 348–360. Objective. To investigate the association between the Trp64Arg β3-adrenergic receptor (ADRB3) mutation and obesity-related phenotypes in a Mediterranean Spanish population considering the effect of other genetic and environmental factors. Design and subject. Cross-sectional study in 1063 (476 men and 587 wome…
Serotonergic polymorphisms in patients suffering from alcoholism, anxiety disorders and narcolepsy.
2001
Abstract 1. Alterations in the serotonergic neurotransmission have been frequently described for patients suffering from alcoholism, anxiety disorders and narcolepsy. 2. The authors tested for association of the 5-HT2A receptor polymorphism (T102C) and the intron 7 tryptophan hydroxylase (TPH) polymorphism (A218C) among 176 alcohol dependent patients, 35 patients with panic disorder, 50 patients with generalized anxiety disorder, 55 patients with narcolepsy and 87 healthy controls. 3. Allele and genotype frequencies of the 5-HT2A receptor polymorphism (T102C), the intron 7 TPH polymorphism (A218C) were almost similar between the patients suffering from alcohol dependence, panic disorder, ge…
Exercise Diminishes Plasma Neurofilament Light Chain and Reroutes the Kynurenine Pathway in Multiple Sclerosis
2020
ObjectiveTo examine acute (single-bout) and training effects of high-intensity interval training (HIIT) vs standard exercise therapy (moderate continuous training [MCT]) on plasma neurofilament light chain (pNfL) and kynurenine (KYN) pathway of tryptophan degradation metabolites in persons with multiple sclerosis (pwMS).MethodsSixty-nine pwMS (Expanded Disability Status Scale score 3.0–6.0) were randomly assigned to a HIIT or an MCT group. Changes in pNfL and KYN pathway metabolites measured in blood plasma were assessed before, after, and 3 hours after the first training session as well as after the 3-week training intervention.ResultsAcute exercise reduced pNfL and increased the KYN pathw…
Adsorption Structures of Amino Acids on Calcite(104)
2015
Elucidating the interaction details of proteins with the most stable cleavage plane of calcite , namely calcite(104), is of great importance for understanding the physicochemical mechanisms behind biomineralisation. In this context, amino acids are generally believed to serve as suitable model molecules, as they constitute the basic building blocks of proteins. In this work, we present a non-contact atomic force microscopy (NC-AFM) investigation of the adsorption of five proteinogenic amino acids on calcite(104) under ultra-high vacuum (UHV) conditions. For studying the structures formed from comparatively large amino acids, enantiopure tryptophan, tyrosine and aspartic acid molecules are d…