Search results for "Transferase"
showing 10 items of 1030 documents
Purification and partial amino acid sequences of the enzyme vinorine synthase involved in a crucial step of ajmaline biosynthesis.
2004
The acetyl-CoA-dependent enzyme vinorine synthase was isolated from hybrid cell suspension cultures of Rauvolfia serpentina and Rhazya stricta. The sarpagan-type alkaloid gardneral was used as a substrate of the enzyme leading to the ajmalan-type 10-methoxyvinorine. An HPLC-based assay was developed to monitor vinorine synthase activity, which allowed establishing a five step purification procedure combining anion exchange, hydrophobic interaction, hydroxyapatite and gel filtration. Purification resulted in a yield of 0.2% and an approximately 991-fold enrichment of the acetyltransfer activity. SDS-PAGE analysis showed a Mr for the enzyme of approximately 50 kDa. The four peptide fragments …
Inhibition of FcεRI-mediated Activation of Rat Basophilic Leukemia Cells by Clostridium difficile Toxin B (Monoglucosyltransferase)
1996
Abstract Treatment of rat basophilic leukemia (RBL) 2H3-hm1 cells with Clostridium difficile toxin B (2 ng/ml), which reportedly depolymerizes the actin cytoskeleton, blocked [3H]serotonin release induced by 2,4-dinitrophenyl-bovine serum albumin, carbachol, mastoparan, and reduced ionophore A23187-stimulated degranulation by about 55-60%. In lysates of RBL cells, toxin B 14C-glucosylated two major and one minor protein. By using two-dimensional gel electrophoresis and immunoblotting, RhoA and Cdc42 were identified as protein substrates of toxin B. In contrast to toxin B, Clostridium botulinum transferase C3 that selectively inactivates RhoA by ADP-ribosylation did not inhibit degranulation…
Thymidine-, uridine- and choline-kinase in rabbit kidney cells infected with herpesvirus hominis, type I and II.
1972
Data are presented about the activity of the thymidine-, uridine- and choline-kinase after infection with 21 strains ofherpesvirus hominis of serotype I or II in rabbit kidney cells. Type I strains increase the activity of the thymidine-kinase 15–20 fold over the controls, whereas the type II strains demonstrate a moderate activity, the level of the enzyme is increased 2–5 fold. One giant cell forming strain exhibits unusual properties, the TK activity decreases in correlation to the controls. The uridine- and choline-kinases induce the respective enzymes in different manner. The strains tested are divided into 5 groups depending upon the activity of the enzymatic activity. The implications…
Induction capacity and influence of dThdMP on thymidine kinase activity of type 1 and 2 strains of herpes simplex virus
1978
The thymidine kinase inducing ability of 104 strains of herpes simplex virus was studied comparatively. A pronounced relationship was established between induction of the enzyme and the serotype of the strains. As a rule, the strains of serotype 2 are weaker inducer of dThd- and dCyd-kinase activity than serotype 1 strains. A certain parallelism exists between induction of both enzymes, however the activity of the thymidine kinase increases after infection with herpes simplex virus 4--5 times more than that of the dCyd-kinase. Adaptation of the strains to cell cultures only slightly modifies the inducing ability of the herpes simplex virus strains. The thymidine kinase activity induced by H…
Evolution and functional differentiation of recently diverged phytochelatin synthase genes from Arundo donax L.
2019
Plant phytochelatin synthases undergo evolutionarily rapid functional differentiation after duplication, allowing fast and precise adjustment of metal detoxification capacity by modulation of both transcription and enzymatic activity.
Functional antagonism between histone H3K4 demethylases in vivo
2011
Dynamic regulation of histone modifications is critical during development, and aberrant activity of chromatin-modifying enzymes has been associated with diseases such as cancer. Histone demethylases have been shown to play a key role in eukaryotic gene transcription; however, little is known about how their activities are coordinated in vivo to regulate specific biological processes. In Drosophila, two enzymes, dLsd1 (Drosophila ortholog of lysine-specific demethylase 1) and Lid (little imaginal discs), demethylate histone H3 at Lys 4 (H3K4), a residue whose methylation is associated with actively transcribed genes. Our studies show that compound mutation of Lid and dLsd1 results in increa…
Investigating the inhibition of FTSJ1 a tryptophan tRNA-specific 2’-O-methyltransferase by NV TRIDs, as a mechanism of readthrough in nonsense mutate…
2023
Abstract: Cystic Fibrosis (CF) is an autosomal recessive genetic disease caused by mutations in the CFTR gene, coding for the CFTR chloride channel. About 10% of the CFTR gene mutations are "stop" mutations, which generate a Premature Termination Codon (PTC), thus synthesizing a truncated CFTR protein. A way to bypass PTC relies on ribosome readthrough, which is the ri-bosome’s capacity to skip a PTC, thus generating a full-length protein. “TRIDs” are molecules exerting ribosome readthrough; for some, the mechanism of action is still under debate. We in-vestigate a possible mechanism of action (MOA) by which our recently synthesized TRIDs, namely NV848, NV914, and NV930, could exert their r…
The role of polymorphisms of thiopurine methyltransferase in therapy with Azathioprine: preliminary study Journal of Biological Research
2018
Azathioprine is an immunosuppressant drug belonging to the class of thiopurines widely used in clinical therapy. Its immunosuppressive action is linked to the substantial action mechanism in the inhibition of the synthesis of nitrogenous bases purine carried out in T-lymphocyte. The level of such medication limit resides in side effects such as myelosuppression and the development of tumours. The occurrence of side effects is linked to the presence of genetic polymorphisms of Thiopurine methyltransferase (TPMT). To date, 40 allelic variants for TPMT have been detected. However, those responsible for the reduction of enzyme activity are three: *2, *3A, *3C. The presence of one of the three p…
Systematic review: macrophage activation syndrome in inflammatory bowel disease.
2013
Summary Background Recently, there have been increasingly frequent reports on the occurrence of macrophage activation syndrome (MAS) in patients with inflammatory bowel disease (IBD). Clinically, MAS is characterized mainly by fever, hepatosplenomegaly, cytopenia, and elevated circulating ferritin and CD25. Mortality, even if diagnosed rapidly, is high. Aim To identify all reports on MAS in IBD and to establish data on triggering agents, immunosuppression leading to MAS, and mortality. Methods A language unrestricted search on Pubmed and Scopus relating to the past 30 years was carried out by matching the following search-terms: h(a)emophagocytic lymphohistiocytosis OR h(a)emophagocytic lym…
dfh is a Drosophila homolog of the Friedreich's ataxia disease gene
2000
Abstract A putative Drosophila homolog of the Friedreich's ataxia disease gene (FRDA) has been cloned and characterized; it has been named Drosophila frataxin homolog (dfh). It is located at 8C/D position on X chromosome and is spread over 1 kb, a much smaller genomic region than the human gene. Its genomic organization is simple, with a single intron dividing the coding region into two exons. The predicted encoded product has 190 amino acids, being considered a frataxin-like protein on the basis of the sequence and secondary structure conservation when compared with human frataxin and related proteins from other eukaryotes. The closest match between the Drosophila and the human proteins in…