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11.
Anu Arya Divya Mathur Abhilash Tyagi Rajesh Kumar Vinod Kumar Carl E. Olsen 《Nucleosides, nucleotides & nucleic acids》2013,32(12):646-659
An efficient protocol has been developed for the synthesis of a small library of 3′-deoxy-3′-(4-substituted-triazol-1-yl)-5-methyluridine using Cu(I)-catalyzed Huisgen–Sharpless–Meldal 1,3-dipolar cycloaddition reaction of 3′-azido-3′-deoxy-5-methyluridine with different alkynes under optimized condition in an overall yields of 76%–92%. Here, the azido precursor compound, i.e., 3′-azido-3′-deoxy-5-methyluridine was chemoenzymatically synthesized from D-xylose in good yield. Some of the alkynes used in cycloaddition reaction were synthesized by the reaction of hydroxycoumarins or naphthols with propargyl bromide in acetone using K2CO3in excellent yields. All synthesized compounds were unambiguously identified on the basis of their spectral (IR, 1H-, 13C NMR spectra, and high-resolution mass spectra) data analysis. 相似文献
12.
Mária Mastihubová Vladimír Mastihuba 《Bioorganic & medicinal chemistry letters》2013,23(19):5389-5392
Methyl α-d-glucopyranoside as a model acceptor was acylated by several phenolic and non-phenolic vinyl esters using immobilised Lipolase. Donor specificity and regioselectivity of reaction were investigated. Conversion and rate of acylation by structurally varied donors indicates that the synthetic reactivity of Lipolase corresponds to the hydrolytic activity of feruloyl esterase type A. Lipolase exhibited remarkable regioselectivity for primary position of methyl α-d-glucopyranoside. The acylation occurred exclusively at 6-O primary position when vinyl esters of phenolic acids (hydroxybenzoates, hydroxyphenylalkanoates and hydroxycinnamates) served as acyl donors (5–77%). In addition to the major 6-O-acyl products (52–79%), 2,6-di-O-acylated derivatives were isolated from reaction mixtures (2–13%) when non-phenolic donors were used (vinyl esters of fully methoxylated derivatives of phenolic acids, along with vinyl benzoates, cinnamates or some heterocyclic analogues). 相似文献
13.
Kelsey H. Fisher-Wellman James A. Draper Michael T. Davidson Ashley S. Williams Tara M. Narowski Dorothy H. Slentz Olga R. Ilkayeva Robert D. Stevens Gregory R. Wagner Rami Najjar Mathew D. Hirschey J. Will Thompson David P. Olson Daniel P. Kelly Timothy R. Koves Paul A. Grimsrud Deborah M. Muoio 《Cell reports》2019,26(6):1557-1572.e8
14.
Vahid Hosseini Christian Dani Mohammad Hossein Geranmayeh Fatemeh Mohammadzadeh Saeed Nazari Soltan Ahmad Masoud Darabi 《Journal of cellular physiology》2019,234(6):8040-8054
The Wnt signaling pathway consists of various downstream target proteins that have substantial roles in mammalian cell proliferation, differentiation, and development. Its aberrant activity can lead to uncontrolled proliferation and tumorigenesis. The posttranslational connection of fatty acyl chains to Wnt proteins provides the unique capacity for regulation of Wnt activity. In spite of the past belief that Wnt molecules are subject to dual acylation, it has been shown that these proteins have only one acylation site and undergo monounsaturated fatty acylation. The Wnt monounsaturated fatty acyl chain is more than just a hydrophobic coating and appears to be critical for Wnt signaling, transport, and receptor activation. Here, we provide an overview of recent findings in Wnt monounsaturated fatty acylation and the mechanism by which this lipid moiety regulates Wnt activity from the site of production to its receptor interactions. 相似文献
15.
16.
Syntheses of acetylated steroid glycosides and selective cleavage of O-acetyl groups in sugar moiety
Acetylated 3β-O-β-glycosyl steroid derivatives were synthesized by the reaction of a new polyhydroxysteroid 3β,5α,6β-trihydroxypregn-16-en-20-one (2) with the peracetylated 1-bromo derivatives of d-glucose and d-galactose, respectively. Subsequent protection by excess acetic anhydride in pyridine selectively gave the 6β-O-acetylated steroid glycosides. Deprotection of the acetylated steroid glycosides separately with moderate catalysis dibutyltin oxide in methanol selectively removed all acetyl groups of sugar moiety, whereas the acetyl group of the steroid part was retained. The structures of the steroid glycosides were confirmed by mass spectrometry, NMR and IR. The complete protocol was shown to be non-destructive at all stages to the sugar moieties and the steroid nucleus. These regioselective reactions open a route to the synthesis of a series of closely related isomers of 2 and other widespread polyhydroxysteroids and steroid glycosides in marine organisms and some terrestrial species. 相似文献
17.
Drepper T Raabe K Giaourakis D Gendrullis M Masepohl B Klipp W 《FEMS microbiology letters》2002,215(2):221-227
A novel esterase catalyzing regioselective hydrolysis was purified from the membrane fraction of Microbacterium sp. 7-1W, and characterized. The enzyme was solubilized with Brij 58 and purified 13.8-fold to apparent homogeneity with 2.58% overall recovery. The relative molecular mass of the native enzyme as estimated by gel filtration was more than 600,000 Da, and the subunit molecular mass was 62,000 Da. The enzyme catalyzed cleavage of the terminal ester bonds of cetraxate esters and pantothenate esters. The K(m) and V(max) values for methyl cetraxate were 0.380 mM and 7.76 micromole min(-1) mg(-1) protein, respectively. The enzyme was inhibited by serine hydrolase inhibitors. 相似文献
18.
Study of the effect of protein chemical acylation on their functional properties or activity often brings valuable information regarding structure-function relationships. We performed such work on wheat lipid transfer protein, LTP1, to investigate the role of grafted acyl chains on the lipid binding and transfer properties. LTP1 was acylated by using anhydride derivatives of various chain lengths from C2 to C6. Only the chemical modifications with hexanoic acid yielded a marked effect on the tertiary structure and a slight change in the secondary structure. The affinity of the modified proteins for myristoyl-lysophosphatidylcholine was similar to that of the native protein accompanied by a slight decrease in stoichiometry. Interestingly, the acylation of LTP1 enhanced the lipid transfer activity by at least a factor of 10 for hexanoic chain length. Finally, the grafting of acyl chains was investigated by means of molecular modelling, and an attempt is made to correlate with our experimental data. 相似文献
19.
The fission yeast plo1(+) gene encodes a polo-like kinase, a member of a conserved family of kinases which play multiple roles during the cell cycle. We show that Plo1 kinase physically interacts with the anaphase-promoting complex (APC)/cyclosome through the noncatalytic domain of Plo1 and the tetratricopeptide repeat domain of the subunit, Cut23. A new cut23 mutation, which specifically disrupts the interaction with Plo1, results in a metaphase arrest. This arrest can be rescued by high expression of Plo1 kinase. We suggest that this physical interaction is crucial for mitotic progression by targeting polo kinase activity toward the APC. 相似文献
20.
Kenneth A. Jacobson Abraham Patchornik 《Journal of biochemical and biophysical methods》1983,8(3):213-222
A series of highly colored nitrophenolates and nitrothiophenolates has been tested as spray reagents for the detection of electrophilic species of the types commonly used in peptide and protein chemistry. Sensitive TLC detection of agents for alkylation, acylation, sulfonylation and phosphorylation was demonstrated. In addition, the thiophenolate sprays were sensitive for oxidizing agents in nanomolar quantities. Selective TLC detection of acylating and phosphorylating agents was accomplished by subsequent alkali treatment resulting in the restoration of color. 相似文献