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Gibberellin A4 monohydrate  [cached]
Yun-Fen Hua,Hai Yan Li,Lin Lin Ma,Xing Zhang
Acta Crystallographica Section E , 2008, DOI: 10.1107/s160053680706062x
Abstract: The title compond, C19H24O5·H2O, has two gibberellin A4 molecules and two water molecules in the asymmetric unit. The A and B rings have chair conformations, whereas the C and D rings have envelope conformations; the two rings which contain the lactone and carbonyl bridge adopt chair and envelope conformations. The crystal structure is established by O—H...O hydrogen bonds and supported by C—H...O hydrogen bonds.
Purification and kinetic studies of recombinant gibberellin dioxygenases
Diane R Lester, Andy Phillips, Peter Hedden, Inger Andersson
BMC Plant Biology , 2005, DOI: 10.1186/1471-2229-5-19
Abstract: Two GA 2ODDs were expressed in Escherichia coli and purified to homogeneity. The GA 2-oxidase from Pisum sativum L., PsGA2OX1, was expressed as a glutathione s-transferase (GST) fusion. It was purified in the three steps of affinity chromatography, GST removal and gel filtration. Highly pure PsGA2OX1 was obtained at a yield of 0.3 mg/g of cells. It displayed a Km of 0.024 μM and a Vmax of 4.4 pkat/mg toward [1β,2β,3β-3H3]GA20. The GA 3-oxidase from Arabidopsis thaliana, AtGA3OX4, was expressed as a poly(His)-tagged thioredoxin fusion. It was purified by Immobilised Metal Affinity Chromatography followed by gel filtration. Cleavage of the fusion took place between the two purification steps. Highly pure AtGA3OX4 was obtained at a yield of 0.01 mg/g of cells. It displayed a Km of 0.82 μM and Vmax of 52,500 pkat/mg toward [1β,2β,3β-3H3]GA20.Fusion tags were required to stabilise and solubilise PsGA2OX1 and AtGA3OX4 during E. coli expression. The successful purification of milligram quantities of PsGA2OX1 enables mechanistic and structural studies not previously possible on GA 2ODDs. A moderate yield of pure AtGA3OX4 requires the further optimisation of the latter stages of the enzyme purification schedule. PsGA2OX1's action in planta as deduced from the effect of the null mutation sln on GA levels in seeds is in agreement with the kinetic parameters of the recombinant enzyme.The 2-oxoglutarate-dependent dioxygenases (2ODDs) of gibberellin (GA) biosynthesis have a key role in plant hormone metabolism. Three principal classes of 2ODDs control the later stages of the pathway where bioactive GA is produced and inactivated (Figure 1). Activation and deactivation of the GA molecule are performed by GA 3-oxidase and GA 2-oxidase enzymes, respectively.The genes encoding GA 2ODDs have been described from many species. They belong to multigene families which show spatial and temporal patterns of expression [1]. Factors including hormone levels and light have been shown to influe
Entanglement quantification and purification in continuous variable systems  [PDF]
S. Parker,S. Bose,M. B. Plenio
Physics , 1999, DOI: 10.1103/PhysRevA.61.032305
Abstract: We develop theoretical and numerical tools for the quantification of entanglement in systems with continuous degrees of freedom. Continuous variable entanglement swapping is introduced and based on this idea we develop methods of entanglement purification for continuous variable systems. The success of these entanglement purification methods is then assessed using these tools.
Purification of a synthetic pterocarpanquinone by countercurrent chromatography
Costa, Fernanda das Neves;Silva, Alcides José M. da;Netto, Chaquip Daher;Domingos, Jorge L. de Oliveira;Costa, Paulo Roberto R.;Leit?o, Gilda G.;
Journal of the Brazilian Chemical Society , 2012, DOI: 10.1590/S0103-50532012000600016
Abstract: countercurrent chromatography (ccc) was employed as a useful, fast and economic alternative to conventional chromatography techniques for the purification of a synthetic pterocarpanquinone, lqb-118. the separation was performed in a two-step ccc with the solvent system hexane-chloroform-methanol-water 2:1.5:5:2 in both steps. traditional purification of these reaction products by silica gel column chromatography demanded a large amount of solvent and time, besides allowing the irreversible adsorption of the compound in the column. the use of 1h nmr for the calculation of kd of target compound is proposed as an alternative for hplc measurements.
Purification of plasmid (pVaxLacZ) by hydrophobic interaction chromatography
Moreira, Keila Aparecida;Diogo, Margarida;Prazeres, Duarte Miguel;Lima Filho, José Luiz de;Porto, Ana Lúcia Figueiredo;
Brazilian Archives of Biology and Technology , 2005, DOI: 10.1590/S1516-89132005000400014
Abstract: this paper describes a method for the plasmid dna purification, which includes an ammonium sulphate precipitation, followed by hydrophobic interaction chromatography (hic) using phenyl sepharose 6 fast flow (low sub). the use of hic took advantage of the more hydrophobic character of single stranded nucleic acid impurities as compared with double-stranded plasmid dna.
Quantification of Acrylamide in Various Belgian Potato Products Using Solid Phase Extraction and Liquid Chromatography Tandem Mass Spectrometry Detection
Food and Public Health , 2012, DOI: 10.5923/j.fph.20120205.04
Abstract: Acrylamide (CH2=CHCONH2), a neurotoxic and potentially carcinogenic substance for human health, is in the glare of the spotlights for a few years. This is mostly due to the fact that acrylamide was found worldwide in various heated foodstuffs. Levels reported in the literature vary from 25 to 2000 μg/kg and potato products are considered as containing the highest level in acrylamide. A possible pathway of synthesis of acrylamide is the Maillard reaction between reducing sugars and the amino acid asparagine. The aim of this study was to develop a liquid chromatography/mass spectrometry method to analyse as quickly as possible acrylamide in a variety of Belgian food samples such as potatoes, French fries, crisp bread, coffee, corn-flakes, etc. The sample preparation consisted in a liquid/liquid extraction, a centrifugation, followed by purification with Solid Phase Extraction (SPE). The instruments used were a Waters 2690 Alliance HPLC system coupled to a Micromass Quattro Ultima Platinum triple-quadrupole mass spectrometer. The analysis was performed in MS/MS mode using isotopic dilution technique for quantification. An internal 13C3 labelled standard was added prior to extraction. Quantification in MS/MS mode was calculated by reconstructing the ion current with the most abundant daughter ions for native and 13C labelled standard (ions of m/z 55 and 58).
Isolation And Purification Of Substance By Column Chromatography
Dr S.N.Meyyanathan
Pharmaceutical Reviews , 2004,
Abstract: In column chromatography, the stationary phase is held in a narrow tube i.e. column and the mobile phase is forced through the tube under pressure or by gravity. Generally silica gel is used as stationary phase which is polar in nature. Substances with higher polarity adsorb more strongly to polar support of silica gel and are eluted more slowly than less polar substances. Thus the least polar substance usually elutes i.e. comes out first from the column and highly polar substance usually elutes last from the column. Solvent can be removed from the eluent by evaporation to isolate the substance in relatively pure form.Procedure: Wash the column with acetone and make it dry. Add the selected mobile phase for the substance to the column while adding the lid at the bottom of column should be in open condition in order to prevent air bubbles. Silica gel (60 – 120 mesh) is then activated by keeping in an oven at 120 Deg.C for 15 minutes. Add the selected mobile phase into the dried silica gel and mix it. Insert a little bunch of cotton into the column above the lid at the bottom of column. Close the lid at the bottom of column and pour the above silica gel and mobile phase mixture into the column uniformly and press with the help of glass rod tightly in order to prevent cracks and air bubbles. Insert cotton over the packed silica gel with the help of a glass rod. Open the lid at the bottom of column and add the mobile phase into the column and run it for 20 minutes. Dissolve the substance (about 1g) in suitable solvent. Close the lid at the bottom of column, add the solution of substance over the top of cotton and finally add the mobile phase over the solution of substance. Wash the test tubes (about 50 No’s) with acetone, dry them and number them from 1 to 50. Prepare the TLC plates using silica gel or use the precoated TLC plates and saturate the chamber or beaker with selected mobile phase for 30 minutes. Open the lid at the bottom of column and collect the fractions of volume around 10 - 20 ml in the test tubes from 1 to 50. Check the TLC for each fraction i.e. solution collected in each test tube by placing o-ne drop of solution of fraction o-n the TLC plates in the beaker. The fractions with single spot showing in TLC can be merged and evaporated, pure substance is isolated which is then subjected to different spectra like IR, NMR, Mass etc. for confirmation of structure of substance. Remaining fractions can be rejected.
Simultaneous Renaturation and Purification of Proteins by Liquid Chromatography

GUO Li-An,GENG Xin-Du,

生物工程学报 , 2000,
Abstract: The recent development of simultaneous renaturation and purification of proteins by liquid chromatography was reviewed.The principles,advantages,and disadvantages for the simultaneous renaruration and purification of proteins by four kinds liquid chromatography,hydrophobic interaction chromatography,ion exchange chromatography,size exclusion chromatography,and affinty chromatography were introduced in details.The new method may be used for researching the refolding of recombinant protein and the simultaneous renaruration and purification of recombinant therapeutic protein in preparative,even in productive scales in industry.This paper contains one table,one figure,and 46 references.
Recent Advances in Protein Purification by Affinity Chromatography

Han Jinyu,Na Ping,Yuan Yingjin,

色谱 , 1996,
Abstract: Affinity chromatography is by far the most powerful technique applied in protein purification and is increasingly used at an industrial scale.Affinity chromatography simplifies separation processes by replacing conventional multistage procedures with a single step ,thereby improving the yield,speed,cost,and efficiency of purification.The technique can be automated,thus reducing labor costs,and giving a sterile pyrogen free product.There are many examples where this technology is applied today for industrial scale purification of proteins.The potential value of affinity chromatography for future production processes is enormous.Recent advances in protein purification by affinity chromatography are introduced in this review.
Improved purification process of β- and α-trypsin isoforms by ion-exchange chromatography
Santos, Alexandre Martins Costa;Oliveira, Jamil Silvano de;Bittar, Eustáquio Resende;Silva, Anderson Louren?o da;Guia, Marcos Luiz dos Mares;Bemquerer, Marcelo Porto;Santoro, Marcelo Matos;
Brazilian Archives of Biology and Technology , 2008, DOI: 10.1590/S1516-89132008000400009
Abstract: the purpose of this work was to improve the separation and yield of pure β- and α-trypsin isoforms by ion-exchange chromatography and to characterize some physical-chemical properties of these isoforms. purification of trypsin isoforms was performed by ion-exchange chromatography in 0.1 mol/l tris-hc buffer, ph 7.10 at 4oc. the sample loading, salt concentration, flow rate and ph of mobile phase were varied to determine their effects on the resolution of the separation. the resolution was optimized mainly between β- and α-trypsin. pure isoforms were obtained by chromatographying 100 mg of commercial trypsin during seven days, yielding 51 mg of high purity β-trypsin and 13 mg of α-trypsin partially pure, with small amounts of contaminating of ψ-trypsin. thus, time and resolution of purification were optimized yielding large amounts of pure active enzymes that are useful for several research areas and biotechnology.
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