Search results for " transglutaminase"

Mass spectrometric identification of the amino donor and acceptor sites in a transglutaminase protein substrate secreted from rat seminal vesicles.

1991

Four different transglutaminase-modified forms of a protein secreted by the rat seminal vesicles (SV-IV) were synthesized in vitro and characterized. FAB maps of both the native protein and its derivatives, produced by the purified guinea pig liver enzyme in the presence or absence of the polyamine spermidine, were obtained by mass spectrometric analysis after proteolytic digestions. Two differently derivatized SV-IV molecular forms, both possessing only one glutamine residue out of two (Gln-86) cross-linked to endogenous lysine residues, were produced when spermidine was omitted from the reaction mixture: (i) an insoluble homopolymer in which Lys-2, -4, -59, -78, -79, and -80 were involved…

The old and new tests for celiac disease: which is the best test combination to diagnose celiac disease in pediatric patients?

2011

BACKGROUND In the diagnosis of celiac disease (CD), serum assays for anti-endomysium (EMA) and anti-transglutaminase (anti-tTG) antibodies have excellent diagnostic accuracy. However, these assays are less sensitive in young pediatric patients. Recently, a new ELISA test using deamidated gliadin peptides (DGP) as antigen has proved to be very sensitive and specific even in pediatric patients. In addition, anti-actin IgA antibodies (AAA) is another test that can be used in CD patients because antibody concentrations correlate with the degree of villous atrophy. This study evaluated the clinical accuracy of anti-tTG, EMA, AGA, anti-DGP and AAA and the effectiveness of these in different combi…

1H NMR Spectroscopy As Tool To Study Transglutaminase Crosslinking Of Pea Globulin

2013

Skiathos Island, GREECE - 30 May - 02 June 2013; International audience; A new method based on NMR spectroscopy was developed to detect the G-L (GlutamylLysine) isopeptide bonds formed by the enzymatic transglutaminase reaction. Because of thecomplexity of NMR signals of proteins due to their structures, the method was first developedon a model system (glutamine and lysine) to simplify the detection of the G-L residue. Andthen, the results were applied on the real protein matrix (pea globulin). MTG treatment ofmodel system led to the appearance of a new resonance on NMR spectrum which isoriginated probably from the ε-methylene protons of lysine residues covalently linked toglutamine. The co…

Conformational Changes in the Nucleosome Followed by the Selective Accessibility of Histone Glutamines in the Transglutaminase Reaction:  Effects of …

2001

Transglutaminases, the enzymes that catalyze the acyl-transfer reaction between glutamine and primary amines, have been used to introduce probes into proteins in order to perform structural studies using physical techniques. Here we use an original approach in which the increasing accessibility of the glutamines of core histones to TGase is used to monitor the salt-induced conformational changes of the nucleosome. The rationale of this strategy is that the accessibility of a glutamine to transglutaminase depends on the blockage due to the presence of either other histones or DNA. At low ionic strength, only glutamines on the N-terminal tails of H2B and H3 are labeled with monodansylcadaveri…

Excitotoxin-induced changes in transglutaminase during differentiation of cerebellar granule cells

2002

Excitotoxicity induced by NMDA receptor stimulation is able to increase the activity of many enzymes involved in neuronal cell death. Primary cultures of rat cerebellar granule cells were used to elucidate the role of transglutaminase reaction in the excitotoxic cell response, and to evaluate the role of glutamate receptors in cell survival and degeneration. Granule neurons, maintained in vitro for two weeks, were exposed to NMDA at different stages of differentiation. Following NMDA receptor activation, increases in transglutaminase activity were observed in cell cultures. The levels of enzyme activity were higher in cells at 5 days in vitro than in those at 8-9 or 13-14 days in vitro. Mor…

Amyloid-Beta Induces Different Expression Pattern of Tissue Transglutaminase and Its Isoforms on Olfactory Ensheathing Cells: Modulatory Effect of In…

2021

Abstract Alzhèimer Disease (AD) is characterized by protein aggregates in the brain, including amyloid-beta (Aβ), a substrate for tissue transglutaminase (TG2). We assessed the effect of full native peptide of Aβ (1–42), the fragments (25–35 and 35–25) on TG2 expression and its isoforms (Long and Short) on mouse Olfactory Ensheathing Cells (OECs). The levels of cytoskeletal proteins, Vimentin and Glial Fibrillary Acid Protein, were also studied. The effect of the pre-treatment with Indicaxanthin on cell viability, total Reactive Oxygen Species, superoxide anion and apoptotic pathway activation was assessed. Since Nestin is co-expressed in pluripotent stem cells with cyclin D1, their levels …

High-performance liquid chromatographic separation of modified and native melittin following transglutaminase-mediated derivatization with a dansyl f…

1991

Abstract The 26-amino acid linear, amphiphilic peptide melittin was enzymatically modified with the fluorescent probe monodansylcadaverine using guinea pig liver transglutaminase and a fluorescent derivative of stoichiometry 1:1 was obtained. Reversed-phase and size-exclusion high-performance liquid chromatographic modes were tested in order to resolve the labelled peptide and native species. The influence of several operational variables was analysed and the elution conditions were optimized so that a satisfactory resolution could be achieved in both instances in a rapid, easy manner. Both chromatographic modes offer the possibility of accurate monitoring of the time course of the enzyme-m…

Anti-transglutaminase autoantibodies in saliva. Usefulness of the radioimmunological test in coeliac children and adolescents: A multicenter study

2013

IgG1 antiendomysium and IgG antitissue transglutaminase (anti-tTG) antibodies in coeliac patients with selective IgA deficiency

2000

Background—In selective IgA deficiency (IgAD), there is no reliable screening test for coeliac disease (CD). Aim—To evaluate the usefulness of IgG1 antiendomysium and IgG antitissue transglutaminase tests for CD diagnosis in IgAD. Methods—IgA and IgG antigliadin antibodies (IgA- and IgG-AGA), IgA and IgG1 antiendomysium antibodies (IgA- and IgG1-EMA), and IgA and IgG antitissue

Selective labelling of melittin with a fluorescent dansylcadaverine probe using guinea-pig liver transglutaminase

1991

Abstract Melittin, a C-terminal peptide, incorporated the fluorescent probe monodansylcadaverine (DNC) when catalysed by guinea-pig liver transglutaminase and Ca2+, as determined by thin-layer chromatography (TLC) and high-performance liquid chromatography (HPLC). A 1:1 adduct DNC-melittin was identified in which a single glutamine residue out of two, i.e. Gln25, acts as acyl donor. Incubation of melittin with transglutaminase in the absence of DNC originated high molecular mass complexes indicative that the peptide lysine residue can act as an acyl acceptor. The DNC-melittin was about 3 times more active in the lysis of red cell membranes than native melittin. Fluorescence study of the lab…