1,720,964 research outputs found
Sviluppo e applicazioni di un bioreattore cromatografico a base di tripsina in drug discovery and drug development
No full textDevelopment of a bioreactor based on immobilized pronase for the on-line digestion and identification of glycoproteins
No full textIdentification of peptides in proteomics supported by prediction of peptide retention by means of quantitative structure-retention relationships
No full textPronase-Immobilized Enzyme Reactor: a New Approach for Automation in Glycoprotein Analysis by LC/LC-ESI/MSn
No full textAn automated analytical approach is proposed for simultaneous
characterization of glycan and peptide moieties
in pronase-generated glycopeptides. The proposed method
is based on the use of a new pronase-immobilized enzyme
reactor for the on-line rapid digestion of the target glycoprotein.
By coupling the bioreactor to a Hypercarb chromatographic
trap column, on-line selective glycopeptide
enrichment prior to normal-phase liquid chromatography-
mass spectrometry was obtained. A detailed study
was carried out for integration and automation of each
phase of the proposed analytical procedure. On-line
digestion allowed extensive cleavage of the model protein
(ribonuclease B), yielding to glycopeptides with peptide
moieties up to eight amino acids, carrying the Man5-Man9
N-glycans each, selectively resolved on an Amide-80
column. The use of a linear ion trap instrument resulted
in efficient ion capture and led to MS3 acquisition times
and spectra quality similar to those for MS2, allowing the
unambiguous identification of glycan (MS2) and peptide
(MS3) sequences. The proposed procedure reduces the
glycoprotein analysis time from 3 days, as in most of
the traditional off-line methods, to 1 h
Pronase-based monolithic bioreactor coupled on-line with LC-MS system for glycoprotein digestion and identification
No full textHuman alpha-1-Microglobulin is Covalently Bound to Kynurenine Derived Chromophores
No full textAlpha-1-Microglobulin carries a set of covalently linked
chromophores that give it a peculiar yellow-brown
color, fluorescence properties, and both charge and size
heterogeneity. In this report it is shown that these features
are due to the adducts with the tryptophan metabolite,
3-hydroxykynurenine, and its autoxidation products
and that the modification is more pronounced in
the protein isolated from urine of hemodialyzed patients.
The light yellow amniotic fluid alpha -1-microglobulin
acquires the optical properties and charge heterogeneity
of the urinary counterpart following incubation with
kynurenines. The colored amino acid adducts of urinary
and amniotic fluid alpha -1-microglobulins were separated
by chromatography after acid hydrolysis and analyzed
by mass spectrometry. Human serum albumin samples,
native and treated with 3-hydroxykynurenine in the
presence of oxygen, were used as a control. The retention
times and mass fragmentation products were compared,
and a lysyl adduct with hydroxantommathin was
identified in the urinary alpha -1-microglobulin and in the
modified albumin samples. The more extensive modification
of the urinary protein appears to be correlated
with uremia, a condition in which the catabolism of
tryptophan via the kynurenine pathway is increased, and
the consequent rise in the concentration of its derivatives is
accompanied by the oxidative processes due to the hemodialysis
treatment. The oxidative derivatives of 3-hydroxykynurenine,
which are known to act as protein crosslinking
agents, are the likely cause of the propensity of
urinary alpha -1-microglobulin to form dimers and oligomers.
This process, as well as the redox properties of these metabolites,
may contribute to the toxic effects of the kynurenine
species
Characterization of phosphorylated proteins: an integrated system for the on-line digestion and selective phosphopeptide analysis by LC/LC-MS/MS
No full text
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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