Possible reaction mechanisms

N-Heterocyclic carbenes are widely used in organic reactions and coordination chemistry. In the present study, 2,3-dihydro-1,3-diisopropyl-4,5-dimethylimidazol-2-ylidene (1) is reacted with diphenyl disulfide, methyl phenyl disulfide, and bis(methylsulfonyl)methane to yield target compounds 5, 6, and 7 respectively.

6p tocectocec 25-05-2020 7 0   Download

We have analyzed several mathematical models that describe inhibition of the factor VIIa–tissue factor complex (VIIa–TF) by tissue factor pathway inhibitor (TFPI). At the core of these models is a common mechanism of TFPI action suggesting that only the Xa–TFPI complex is the inhibitor of the extrinsic tenase activity. However, the model based on this hypothesis could not explain well all the available experimental data. Here, we show that a good quantitative description of all experimental data could be achieved in a model that contains two more assumptions....

16p research12 01-06-2013 37 6   Download

The crystal structure of citrate synthase from the thermo-philic ArchaeonSulfolobus solfataricus(optimum growth temperature ¼85
C) has been determined, extending the number of crystal structures of citrate synthase from differ-ent organisms to a total of five that span the temperature range over which life exists (from psychrophile to hyper-thermophile). Detailed structural analysis has revealed possible molecular mechanisms that determine the different stabilities of thefiveproteins.

11p tumor12 22-04-2013 61 3   Download

DNA ligases are the enzymes responsible for the repair of single-strandedanddouble-strandednicks indsDNA.DNA ligases are structurally similar, possibly sharing a common molecular mechanism of nick recognition and ligation catalysis. This mechanism remains unclear, in part because the structure of ligase in complex with dsDNAhas yet to be solved.DNA ligases share common structural elementswith DNA polymerases, which have been cocrystallized with dsDNA. Based on the observed DNA polymerase–dsDNA interactions, we propose a mechanism for recognition of a single-stranded nick by DNA ligase....

7p tumor12 22-04-2013 39 2   Download

One of the hallmarks of cAMP is its ability to inhibit proliferation in many cell types, but stimulate proliferation in others. Clearly cAMP has cell type specific effects and the outcome on proliferation is largely attributed to crosstalk from cAMP to the RAS⁄RAF⁄mitogen-activated protein kinase (MAPK) and extracellular signal-regulated kinase (ERK) kinase (MEK)/ ERK pathway. We review the crosstalk between these two ancient and con-served pathways, describing the molecular mechanisms underlying the interactions between these pathways and discussing their possible biological importance....

14p fptmusic 11-04-2013 41 3   Download

Hypoxia and hypoxia-related genes are important factors in articular chon-drocytes during cartilage homeostasis and osteoarthritis. We have investi-gated the various apoptotic factors that show significance in synovial fluid obtained from normal and experimental osteoarthritic animal models and have evaluated the effect of hypoxia on articular chondrocyte apoptosis induced by these apoptotic factors.

11p vinaphone15 28-02-2013 37 2   Download

Toll-like receptor 4 (TLR4) plays an important role in innate immunity. The role of TLR4 in stretched cardiomyocytes is not known. We sought to investigate whether mechanical stretch could regulate TLR4 expression, as well as the possible molecular mechanisms and signal pathways mediating the expression of TLR4 by cyclic mechanical stretch in cardiomyocytes. Methods: Neonatal Wistar rat cardiomyocytes grown on a flexible membrane base were stretched by vacuum to 20% of maximum elongation at 60 cycles/min.

13p toshiba23 18-11-2011 70 3   Download