Triggering cascade

Figure 6.69 An enantioconvergent enzyme-triggered cascade reaction.

Scheme 5.6 Glutathione-triggered cascade drug release for tumor-targeting of fluoro-taxoid conjugates.

A tellurium ion-triggered cascade was reported by Dittmer as a method to synthesize isobenzofuran derivatives. Exposing epoxide 403 to Te 2 under phase transfer conditions afforded dihydroisobenzofuran 404 in 90% yield (Scheme 74) (00TL6001). The mechanism of this reaction presumably begins by SN2... 

Ogura, T., Evans, R. 1995a. A retinoic acid-triggered cascade of Hoxb-1 gene activation. Proc. Natl. Acad. Sci. USA 92, 387-391. 

After a brief overview of signal transduction, the text describes the structure of the seven-helix transmembrane P-adrenergic receptor and indicates how it transmits to the intracellular side of the plasma membrane a signal arising from binding the hormone epinephrine on the extracellular surface of the cell. The common features of the G proteins are presented next. The description of the information-transmission pathway from hormone stimulus to G proteins to adenylate cyclase is completed by a discussion of how cAMP activates specific protein kinases to modulate the activities of the phosphorylated target proteins. A small number of hormone molecules outside the cell results in an amplified response because each activated enzyme in the triggered cascade forms numerous products. There are many distinct seven-helix transmembrane hormone receptors. 

Hu, J., Xian, B., Wu, X. Y., Tong, X. R (2012). Tertiary amine-triggered cascade S(N)2/cycloaddition an efficient construction of complex azaheterocycles under mUd conditions. Organic Letters, 14, 5074-5077. 

The surface chemistry of implants plays an important role in their service. During implantation, proteins and other biomolecules adsorb on the implant s surface. The changes in native conformations of biomolecules on a non physiological surface initiate a trigger cascade of inflammatory (immune) responses, which interfere with the integration of the implant into the living tissue or enhance the formation of fiber capsule. A cer-... 

Enantioconvergent enzyme-triggered cascade reaction of rac-c/s-1-chioro-2,3-epoxyheptane as a key step for the total synthesis of a (+)-Jamaican rum constituent and (+)-pestaiotin. 

Mayer, S.F., Steinreiber, A., Goriup, M., Saf, R. and Faber, K. (2002) Chemoenzymatic asymmetric total syntheses of a constituent of Jamaican rum and of (+)-Pestalotin using an enantioconvergent enzyme-triggered cascade reaction. Tetrahedron Asymmetry, 13, 523-528. 

Ions arrive at one end of each element of a multipoint collector and trigger a cascade of electrons, which moves toward the opposite end and is detected electronically. The resulting electric current corresponds to the ion current. 

CC, and one CX3C and XC chemokine receptors have been cloned so far [2]. Receptor binding initiates a cascade of intracellular events mediated by the receptor-associated heterotrimeric G-proteins. These G-protein subunits trigger various effector enzymes that lead to the activation not only of chemotaxis but also to a wide range of fimctions in different leukocytes such as an increase in the respiratory burst, degranulation, phagocytosis, and lipid mediator synthesis. 

A cascade of proteins of the immune response that can be triggered by antigen-antibody complexes and by the innate immune system (e.g. exposure to microbial polysaccharides) to raise the immune response. Complement proteins can detect and bind to foreign material or immune complexes and label them for phagocytosis. They can also cause inflammation by directly degranulating mast cells and releasing chemokines to recruit other immune cells into the affected area. 

Khodorova A, Navarro B, Jouaville LS et al (2003) Endothelin-B receptor activation triggers an endogenous analgesic cascade at sites of peripheral injury. Nat Med 9 1055-1061... 

Acute over-activation of NHE1 results in a marked elevation in intracellular sodium concentration with a subsequent increase in intracellular calcium, via the Na +/Ca++ exchanger. This in turn triggers a cascade of injurious events that can culminate in tissue dysfunction and ultimately apoptosis and necrosis. This is commonly seen in organs such as the heart, brain and kidneys as a consequence of ischemia-reperfusion. 

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