共查询到20条相似文献,搜索用时 203 毫秒
1.
Patel RN 《Current opinion in biotechnology》2001,12(6):587-604
There has been an increasing awareness of the enormous potential of microorganisms and enzymes for the transformation of synthetic chemicals with high chemo-, regio- and enantioselectivity. Chiral intermediates and fine chemicals are in high demand, both from the pharmaceutical and agrochemical industries, for the preparation of bulk drug substances and agricultural products. Biocatalytic processes have been described for the synthesis of chiral intermediates for beta3- and beta2-receptor agonists, antihypertensive drugs, antiviral agents, melatonin receptor agonists, anticholesterol and anticancer drugs, and drugs to treat Alzheimer's disease. 相似文献
2.
3.
Phthalimido-alkyl alcohol solid supports were rapidly prepared from solid supported phthalic anhydride and amino alcohol condensation induced by microwaves. These supports were used to synthesize 13-aminoalkyl oligodeoxynucleotides allowing a two step deprotection necessary to avoid aminolink alkylation. 相似文献
4.
5.
6.
Choi WJ Moon HR Kim HO Ko YM Kim HJ Lee JA Lee KM Yun MK Shin DH Chun MW Sheen YY Kim K Jeong LS 《Nucleosides, nucleotides & nucleic acids》2005,24(5-7):611-613
The preparative and stereoselective synthesis (45- 50% overall yields, >50 g scale) of the key carbasugars 7a-d was achieved from D-ribose via stereoselective Grignard reaction and oxidative rearrangement as key reactions. 相似文献
7.
Wallace R 《Comptes rendus biologies》2010,333(10):701-709
The Modern Evolutionary Synthesis formalizes the role of variation, heredity, differential reproduction and mutation in population genetics. Here we explore a mathematical structure, based on the asymptotic limit theorems of communication theory, that instantiates the punctuated dynamic relations of organisms with their embedding environments, including the possibility of the transfer of heritage information between different classes of organism. The approach applies a standard coevolutionary argument to genes, environment, and gene expression reconfigured as interacting information sources. In essence, we provide something of a formal roadmap for the modernization of the Modern Synthesis, making applications to both relatively rapid evolutionary punctuated equilibrium and to the conservation of ecological interactions across deep evolutionary time. 相似文献
8.
9.
Nadine Barroca-Aubry 《Carbohydrate research》2010,345(12):1685-1697
The total chemical synthesis of the four well-defined chitodisaccharides is described using N-trichloroacetyl (TCA) and N-benzyloxycarbonyl (Z) as C-2 protecting groups for acetamido and free amino groups, respectively. The synthesis is carried out according to a strategy that paves way to the elaboration of various homo- and hetero-chitooligosaccharides, with perfect control of the number and the position of GlcN and GlcNAc units along the oligomer chain. 相似文献
10.
Regulation of the synthesis of acetylcholine 总被引:1,自引:0,他引:1
11.
12.
An effective synthesis of isoorientin: the regioselective synthesis of a 6-C-glucosylflavone 总被引:3,自引:0,他引:3
Isoorientin, a 6-C-beta-D-glucopyranosyl-3',4',5,7-tetrahydroxyflavone, was synthesized in a 15% overall yield, in ten steps, starting from the commercially available phloroacetophenone. The C-glucosyl phloroacetophenone derivative, a synthetic intermediate that contains a free hydroxyl group that is para to the glucosyl moiety, was obtained by hydrogenolysis by taking advantage of differences in the hydrogenolysis rates between a benzyl protecting group and a 2-methylbenzyl protecting group. Aldol condensation of the C-glucosyl phloroacetophenone derivative with 3,4-bis-benzyloxybenzaldehyde afforded the corresponding chalcone as a precursor of the 6-C-glucosyl flavone. Construction of the flavone system by application of I2-DMSO, followed by deprotection, yielded isoorientin. 相似文献
13.
14.
15.
16.
Towards the mechanism of cellulose synthesis 总被引:9,自引:0,他引:9
Recent research has provided insights into how plants make cellulose - the major structural material of their cell walls and the basis of the cotton and wood fibre industries. Arabidopsis thaliana mutants impaired in cellulose production are defective in genes encoding membrane-bound glycosyltransferases, an endo-1,4-beta-glucanase and several enzymes involved in the N-glycosylation and quality-control pathways of the endoplasmic reticulum. The glycosyltransferases form the rosette terminal complexes seen in plasma membranes making cellulose. Synthesis might start by making lipoglucans, which, in turn, might form the substrate for the endo-1,4-beta-glucanase, before being elongated to form the long, crystalline microfibrils that assemble in the cell wall. 相似文献
17.
Anna Coslovi Cristiana Campa Anna Flamigni Marco Rossi Amedeo Vetere Fulvio Uggeri Sergio Paoletti 《Journal of Molecular Catalysis .B, Enzymatic》2007,45(3-4):128-134
The enzymatic synthesis of the Tn antigen (GalNAc-α-O-Ser), a glyco-aminoacid of great biological importance, is reported. The reaction was promoted by commercial α-N-acetylgalactosaminidase from Acremonium sp., using p-nitrophenyl-α-N-acetylgalactosamine as the donor. The kinetics were monitored by capillary electrophoresis and LC–UV-MS. For unprotected serine, the role of pH and temperature was investigated, finding that pH 5 and T = 18 °C gave the best yield. Under these conditions a significant increase of the reaction rate was observed in comparison with previous literature data, using unprotected serine. The role of the bulkiness of the serine protecting groups on the yield was additionally considered, as well as the kinetic profiles generated by the use of two differently protected aminoacids. By proper choice of the protecting group, the reaction yield then increased from 5% (with unprotected serine) to about 50% (with N-Boc and N-methoxycarbonyl serine). 相似文献
18.
19.
A.Ian Scott 《Bioorganic chemistry》1974,3(4):398-429
A review of the rationale and methodology for the laboratory construction of the major classes of indole alkaloid based on their known or presumed biosynthesis is presented. The experimental results obtained provide analogies for the principal condensation and rearrangement reactions uncovered in biochemical investigations in this field and suggest new incorporation experiments. The prediction and discovery of new classes of alkaloid based on the observed transformations have been made and, in turn, new theories have been developed to explain some of the hitherto unsolved problems of biotransformation and structure in this series.Finally, the suggestion is made that many of the complex structures encountered in the various families may arise through rather unspecific processes, some indeed of a nonenzymic nature. 相似文献
20.
In this issue of Structure, Rymer and colleagues present the first crystal structures of a bacterial DnaG primase with bound substrate NTPs and alarmone inhibitors. A thoughtful comparative structural analysis provides important insights into the chemical mechanism of primase. 相似文献