- Template effects of vesicles in dynamic covalent chemistry
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Vesicle lipid bilayers have been employed as templates to modulate the product distribution in a dynamic covalent library of Michael adducts formed by mixing a Michael acceptor with thiols. In methanol solution, all possible Michael adducts were obtained in similar amounts. Addition of vesicles to the dynamic covalent library led to the formation of a single major product. The equilibrium constants for formation of the Michael adducts are similar for all of the thiols used in this experiment, and the effect of the vesicles on the composition of the library is attributed to the differential partitioning of the library members between the lipid bilayer and the aqueous solution. The results provide a quantitative approach for exploiting dynamic covalent chemistry within lipid bilayers. This journal is
- Bravin, Carlo,Hunter, Christopher A.
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p. 9122 - 9125
(2020/09/17)
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- The Antimalarial Natural Product Salinipostin A Identifies Essential α/β Serine Hydrolases Involved in Lipid Metabolism in P. falciparum Parasites
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Salinipostin A (Sal A) is a potent antiplasmodial marine natural product with an undefined mechanism of action. Using a Sal A-derived activity-based probe, we identify its targets in the Plasmodium falciparum parasite. All of the identified proteins contain α/β serine hydrolase domains and several are essential for parasite growth. One of the essential targets displays a high degree of homology to human monoacylglycerol lipase (MAGL) and is able to process lipid esters including a MAGL acylglyceride substrate. This Sal A target is inhibited by the anti-obesity drug Orlistat, which disrupts lipid metabolism. Resistance selections yielded parasites that showed only minor reductions in sensitivity and that acquired mutations in a PRELI domain-containing protein linked to drug resistance in Toxoplasma gondii. This inability to evolve efficient resistance mechanisms combined with the non-essentiality of human homologs makes the serine hydrolases identified here promising antimalarial targets. Using a probe analog of the antimalarial natural product Sal A, Yoo et al. identify its targets as multiple essential serine hydrolases, including a homolog of human monoacylglycerol lipase. Because parasites were unable to generate robust in vitro resistance to Sal A, these enzymes represent promising targets for antimalarial drugs.
- Bogyo, Matthew,Boucher, Michael J.,Cieplak, Piotr,Fidock, David A.,Foe, Ian T.,Gn?dig, Nina F.,Kumpornsin, Krittikorn,Kurita, Kenji,Lee, Marcus C. S.,Linington, Roger G.,Long, Jonathan Z.,Mok, Sachel,Onguka, Ouma,Schulze, Christopher J.,Stokes, Barbara H.,Terrell, Stephanie M.,Uhlemann, Anne-Catrin,Weerapana, Eranthie,Yeo, Tomas,Yoo, Euna,Zhou, Yani
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p. 143 - 157
(2020/02/18)
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- Keratinocyte growth factor-2 formulations
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The invention is directed to liquid and lyophilized forms of Keratinocyte Growth Factor-2 (KGF-2) and derivatives thereof. This invention further relates to the formulation of KGF-2 for therapeutic use, for example, to promote or accelerate wound healing.
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- YELLOW COMPOUND AND WATER-BASED INK-JET RECORDING INK CONTAINING THE COMPOUND
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Aqueous ink for ink-jet recording which contains at least a water-insoluble coloring matter, water and a resin as main components and which takes the form of an emulsion, in which is characterized by containing at least one yellow hue coloring matter selected from the group consisting of a quinophthalone compound represented by the formula (1); and a pyridone azo compound represented by the formula (2); The ink is ink for ink-jet recording having excellent light resistance and storage stability, and enables formation of a high quality image without blotting, and obtained recording image is excellent in water resistance as ink for ink-jet recording.
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- Aqueous ink for ink jet recording
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Aqueous ink for ink jet recording which contains at least a water-insoluble coloring matter, water and a resin as main components and which takes the form of an emulsion, the coloring matter being represented by formula (1) The coloring matter for ink jet recording of the invention is excellent in water resistance in particular and also excellent in light resistance and compatibility with the resin. Thus, it is suited for ink jet recording. Further, the aqueous ink for ink jet recording of the invention which is produced using the coloring matter is excellent in light resistance and storage stability. Especially, when it is used as ink for ink jet recording system, the use of the ink composition can provide excellent aqueous ink that enables formation of a high-quality image without blotting and a recorded image having an excellent water resistance.
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- Reaction of ascorbic acid with S-nitrosothiols: Clear evidence for two distinct reaction pathways
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Ascorbate reacts with S-nitrosothiols generally, in the pH range 3-13 by way of two distinct pathways, (a) at low [ascorbate], typically below ～1 × 10-4 mol dm-3 which leads to the formation of NO and the disulfide, and (b) at higher [ascorbate] when the products are the thiol and NO. Reaction (a) is Cu2+-dependent, and is completely cut out in the presence of EDTA, whereas reaction (b) is totally independent of [Cu2+] and takes place readily whether EDTA is present or not. For S-nitrosoglutathione (GSNO) the two reactions can be made quite separate, although for some reactants the two reactions overlap. In reaction (a), ascorbate acts as a reducing agent, generating Cu+ from Cu2+, which in turn reacts with RSNO forming initially NO, Cu2+ and RS-. The latter can then play the role of reducing agent for Cu2+, leading to disulfide formation. Ascorbate will initiate reaction when the free thiolate has initially been reduced to a very low level by the synthesis of RSNO from a large excess of nitrous acid over the thiol. Reaction (b) is interpreted in terms of nucleophilic attack by ascorbate at the nitroso-nitrogen atom, leading to thiol and O-nitrosoascorbate which breaks up, by a free-radical pathway, to give dehydroascorbic acid and NO. A similar pathway is the accepted mechanism in the literature for the nitrosation of ascorbate by nitrous acid and alkyl nitrites. The rate constant for the Cu2+-independent pathway increases sharply with pH and analysis of the variation of the rate constant with pH identifies a reaction pathway via both the mono- and di-anion forms of ascorbate, with the latter being the more reactive. As expected the entropy of activation is large and negative. Some aspects of structure-reactivity trends are discussed.
- Holmes, Anthony J.,Williams, D. Lyn H.
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p. 1639 - 1644
(2007/10/03)
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- Cephalosporin derivatives
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7 α-formamido cephalosporin derivatives having a 3[N-(optionally substituted)aminothiopyridinium thiomethyl] substituent have anti-bacterial activity and are of use in anti-bacterial therapy. Processes for the preparation thereof and intermediates for use in these processes are also disclosed.
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- Process for preparing stabilizers containing sulfur and a hindered phenol group
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Compounds of the formula I STR1 in which R1 and R2, independently, denote alkyl with 1 to 6 carbon atoms, cycloalkyl with 5 to 8 carbon atoms, allyl, methallyl, aralkyl with 5 to 9 carbon atoms, phenyl, 1- or 2-naphthyl, or alkaryl with 7 to 9 carbon atoms, R2 moreover also denotes hydrogen, R3 denotes hydrogen, alkyl with 1 to 6 carbon atoms, unsubstituted phenyl or phenyl substituted by one or two chlorine atoms and/or one or two methyl groups, B denotes a hetero atom, the group --OC(O)--, --OC(O)--CH2 CH2 -- or a direct bond, m is an integer from 0 to 6, and n is an integer from 1 to 6, are prepared by reaction of a thioglycerol derivative with a carboxylic acid containing the hindered phenol moiety in the presence of an acid and are used as antioxidants and thermal stabilizers for lubricating oils, plastics, resins and other organic substrates.
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- Organotin-containing composition for the stabilization of polymers of vinyl chloride
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An organotin-containing composition for the stabilization of polymers or copolymers of vinyl chloride in which there is incorporated a stabilizing amount of an organotin compound containing at least two tin atoms and which is a mercapto, hydroxy or alkoxy substituted ester of a mercapto acid substituted organotin mercapto acid diester.
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- Preparation of mercapto-alcohols
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A process for preparing mercapto-alcohols by reacting a molar excess of hydrogen sulfide with an alkylene, cycloalkylene, or aralkylene oxide in the presence of an alkali metal zeolite catalyst.
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