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1.
Enzymatic transformation of cephalosporin C to 7-ACA by simultaneous action of immobilized d-amino acid oxidase and glutaryl-7-ACA acylase 总被引:2,自引:0,他引:2
Daniele Bianchi Rossella Bortolo Paolo Golini Pietro Cesti 《Applied biochemistry and biotechnology》1998,73(2-3):257-268
The enzymatic transformation of cephalosporin C (CEPH C) to 7-amino-cephalosporanic acid (7-ACA) using D-amino acid oxidase
(DAO) and glutaryl-7-ACA acylase (G1-7-ACA) is reported. The enzymes have been immobilized separately on different carriers,
in order to maximize the catalytic activity and the stability. The reaction has been carried out in single-step-like conditions,
using the two enzymes simultaneously. The effect of catalase contamination, present in the DAO preparations, was balanced
by addition of extra hydrogen peroxide. In optimum conditions, the conversion of CEPH C to 7-ACA was higher than 90%, with
byproduct formation lower than 4%. The mixture of immobilized enzymes was reused in repeated reaction cycles, showing an appreciable
operational stability. 相似文献
2.
Synthetic methods for cephalosporin G derivatized at the carboxyl were developed. Dinitroglycerine, acetoxymethyl, and choline
esters of cephalosporin G and its amide in addition to amides of cephalosporin G with glutamic acid and arginine were synthesized.
__________
Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 85–88, January–February, 2007. 相似文献
3.
Microwave-Assisted Solid-Phase Synthesis of Cephalosporin Derivatives with Antibacterial Activity 总被引:1,自引:0,他引:1
Mazaahir Kidwai Preeti Misra Kumar R. Bhushan Rajendra K. Saxena Meena Singh 《Monatshefte für Chemie / Chemical Monthly》2000,131(9):937-943
Summary. The reaction of heterocyclic acids with 7-amino-cephalosporanic acid adsorbed on basic alumina under microwave irradiation
afforded the N-acylated cephalosporin analogues in satisfactory yield. All compounds were tested for their antibacterial activity;
some of them showed significant antibacterial properties. Cefotaxime and cephalothin were used as reference drugs.
Received February 23, 2000. Accepted March 28, 2000 相似文献
4.
Glutaryl-7-aminocephalosporanic acid (GL-7-ACA) acylase isan enzyme that converts GL-7-ACA to 7-aminocephalosporanic acid,
a starting material for semisynthetic cephalosporin antibiotics. In this study, optimal conditions for the immobilization
of GL-7-ACA acylase were determined by experimental observations and statistical methods. The optimal conditions were as follows:
1.1 M phosphate buffer (pH 8.3) as buffer solution, immobilization temperature of 20°C, and immobilization time of 120 min. Unreacted
aldehydegroups were quenched by reaction with a low-molecular-weight material such as l-lysine, glycine, and ethanolamine after immobilization in order to enhance the activity of immobilized GL-7-ACA acylase.
The activities of immobilized GL-7-ACA acylase obtained by using the low-molecular-weight materials were higher than those
obtained by immobilized GL-7-ACA acylase not treated with low-molecular-weight materials. In particular, the highest activity
of immobilized GL-7-ACA acylase was obtained using 0.4% (v/v) ethanolamine. We also investigated the effect of sodium cyanoborohydride
in order to increase the stability of the linkage between the enzyme and the support. The effect on operational stability
was obvious: the activity of immobilized GL-7-ACA acylase treated with 4% (w/w) sodium cyanoborohydride remained almost 100%
after 20 times of reuse. 相似文献
5.
Kazuhiro Yamamoto Hideki Hakamata Akira Yamaguchi Fumiyo Kusu 《Analytical and bioanalytical chemistry》2009,395(2):533-538
A simple method was developed for monitoring the permeation of medium-chain fatty acids of C8 (octanoic acid) and C10 (decanoic
acid) through CaCo-2 cell monolayers by high-performance liquid chromatography with electrochemical detection (HPLC-ECD).
The detection was made based on the electrochemical reduction prepeak of quinone caused by acids, requiring the fabrication
of a two-channel HPLC-ECD system. In one channel, acetonitrile–water (7:3, v/v) was used as a mobile phase to separate acids by a C30 column. In the other channel, acetonitrile–water (7:3, v/v) containing 6 mmol/L 3,5-di-t-butyl-1,2-benzoquinone and 20 mmol/L LiClO4 was used as a quinone solution to detect acids by an electrochemical cell with a glassy carbon working electrode. In this
HPLC-ECD system, eluted acids were mixed with the quinone solution in a post column fashion to obtain current signals caused
by acids. The peak area was found to be linearly related to the acid amount ranging from 25 to 1,000 pmol (r > 0.992). The detection limits of octanoic acid and decanoic acid were 7.5 and 8.8 pmol, respectively. Octanoic acid and
decanoic acid spiked into cell culture media samples were extracted with acetonitrile and their recoveries were more than
89.5% with an RSD of less than 8.2%. This method was applied to the permeation experiment of octanoic acid and decanoic acid
with CaCo-2 cell monolayers formed on the Transwell? system.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.
This work was partly presented at The Physical Pharma Forum 2008 on March 24, 2008 in Tokyo, Japan. 相似文献
6.
Reusability of entrapped cells of Pseudomonas diminuta for production of 7-aminocephalosporanic acid
Entrapped cells of P. diminuta were used for the production of 7-aminocephalosporanic acid (7-ACA), a key intermediate required for the production of most
of the clinically used cephalosporin derivatives, i.e., semisynthetic cephalosporins. The repeated batch production of 7-ACA
with entrapped cells of P. diminuta in different carriers were carried out for six cycles at optimal conditions. It was found that 33%, 38%, and 47% of activity
was lost with chitosan, gelatin, and agar, respectively as immobilizing supports after the sixth cycle of operation. 相似文献
7.
It has been shown by the methods of X-ray powder diffraction (XRD), differential thermal analysis (DTA) and infrared spectroscopy
(IR) that solid solutions of a formula Cr1−xAlxVMoO7, where xε (0−0.65), are formed in the system CrVMoO7-AlVMoO7. The obtained research results have proven that the ions Al3+ are incorporated into the crystal lattice of CrVMoO7 instead of Cr3+, which causes a contraction of the lattice and a shift of IR absorption bands towards higher values of wavenumbers. The phases
Cr1−xAlxVMoO7 melt incongruently in the temperature range from 710°C (for x=0.65) to ∼820°C in the case of x close to zero
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
8.
Emese Szabó Jérémy Tarmoul Alexandre Tomas Christa Fittschen Sándor Dóbé Patrice Coddeville 《Reaction Kinetics and Catalysis Letters》2009,96(2):299-309
Kinetics of the •OH-initiated reactions of acetic acid and its deuterated isomers have been investigated performing simulation chamber experiments
at T = 300 ± 2 K. The following rate constant values have been obtained (± 1σ, in cm3 molecule−1 s−1): k
1(CH3C(O)OH + •OH) = (6.3 ± 0.9) × 10−13, k
2(CH3C(O)OD + •OH) = (1.5 ± 0.3) × 10−13, k
3(CD3C(O)OH + •OH) = (6.3 ± 0.9) × 10−13, and k
4(CD3C(O)OD + •OH) = (0.90 ± 0.1) × 10−13. This study presents the first data on k
2(CH3C(O)OD + •OH). Glyoxylic acid has been detected among the products confirming the fate of the •CH2C(O)OH radical as suggested by recent theoretical studies. 相似文献
9.
Simone Schiesel Michael Lämmerhofer Wolfgang Lindner 《Analytical and bioanalytical chemistry》2010,397(1):147-160
In the present paper, we report on the development of a straightforward reversed-phase liquid chromatography–electrospray
ionization–tandem mass spectrometry method for the determination of the most abundant fatty acids; α-tocopherol and cephalosporin
P1 in fermentation broths. Using this method, fatty acids could be successfully determined in extracts of fermentation broths
from penicillin and cephalosporin production without prior derivatization. Matrix effects were investigated in detail, and
various kinds of calibrations (i.e., by use of neat standard solutions as well as by matrix-matched calibration employing
standard addition each with and without internal standards) were comparatively assessed. The optimized and validated method
was employed for the analysis of extracts of fermentation broths and nutrition media. 相似文献
10.
Syntheses and X‐ray structural characterizations of two new Cu(II) complexes Cu(tfbz)2(Htfbz)2(phen) ( 1 ) (Htfbz=2,4,5‐trifluorobenzoic acid, phen=1,10‐phenanthroline) and [Cu(pfbz)2(phen)]2(Hpfbz)2 ( 2 ) (Hpfbz=pentafluorobenzoic acid) are reported. The first complex crystallizes in the monoclinic space group C2/c with the crystal cell parameters a=1.9903(4) nm, b=1.3688(3) nm, c=1.3623(3) nm, β=97.90(3)°, V=3.6762(13) nm3 and Z=4. The second complex crystallizes in the triclinic space group P‐1 with the crystal cell parameters a=1.7965(4) Å, b=1.9236(2) Å, c=2.0916(2) Å, α=110.156(2) °, β=105.040(3) °, γ=98.123(3) °, V=6.3372(17) nm3 and Z=4. The crystallographic analyses revealed that F···H–C hydrogen bonds in both complexes lead to formation of infinite three‐dimensional supramolecular networks. A large number of F···F interactions in complex 2 ensure the stability of intricate crystal structure. 相似文献
11.
Araujo M. Lucia G. C. Giordano Roberto C. Hokka Carlos O. 《Applied biochemistry and biotechnology》1998,(1):493-504
Cells ofCephalosporium acretnonium ATCC 48272 immobilized in calcium alginate beads were utilized for cephalosporin C production and the results were compared
with those obtained with free cells. The experiments were performed with synthetic medium containing glucose and sucrose as
carbon and energy sources. Experimental effectiveness factor values were obtained at various cell and dissolved-oxygen concentrations,
considering Monod kinetics for the respiration rate, and were compared with the values calculated with zero-order kinetics
in spherical bioparticle. The results showed that the assumption of oxygen limitation by diffusion in the bioparticle was
correct, and that cephalosporin C production with immobilized cells is perfectly viable, although a slightly lower rate than
that obtained in the free cell process was observed. 相似文献
12.
S. Jingyan L. Jie D. Yun H. Ling Y. Xi W. Zhiyong L. Yuwen W. Cunxin 《Journal of Thermal Analysis and Calorimetry》2008,93(2):403-409
The thermal behavior of nicotinic acid under inert conditions was investigated by TG, FTIR and TG/DSC-FTIR. The results of
TG/DSC-FTIR and FTIR indicated that the thermal behavior of nicotinic acid can be divided into four stages: a solid-solid
phase transition (176–198°C), the process of sublimation (198–232°C), melting (232–263°C) and evaporation (263–325°C) when
experiment was performed at the heating rate of 20 K min−1. The thermal analysis kinetic calculation of the second stage (sublimation) and the fourth stage (evaporation) were carried
out respectively. Heating rates of 1, 1.5, 2 and 3 K min−1 were used to determine the sublimation kinetics.
The apparent activation energy, pre-exponential factor and the most probable model function were obtained by using the master
plots method. The results indicated that sublimation process can be described by one-dimensional phase boundary reaction,
g(α)=α. And the ‘kinetic triplet’ of evaporation process was also given at higher heating rates of 15, 20, 25, 30 and 35 K min−1. Evaporation process can be described by model of nucleation and nucleus growing, . 相似文献
13.
Thermal decomposition process of solid state poly(β -L-malic acid) was traced by DSC combined with FT-IR. Melting temperature of this partially crystallized polymer was detected
at 46-60°C. The thermal decomposition initiated at ca 185°C accompanied by an evolution of gaseous products. In contrast to
the cleavage reaction in the aqueous polymer solutions which gives L-malic acid and corresponding dimer of L-malic acid, the solid state poly(β -L-malic acid) decomposed at above the decomposition temperature giving not the constituent L-malic acid but fumaric acid at the first stage of the reaction then, maleic and maleic anhydride.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
14.
P. F. Vlad M. N. Coltsa A. N. Aricu A. G. Ciocarlan E. C. Gorincioi C. G. Edu C. Deleanu 《Russian Chemical Bulletin》2006,55(4):703-707
An efficient two-step procedure for photooxidative dehydrogenation of drimane and 11-homodrimane compounds containing an 8-en-7-one
structural unit into α,α′-dienones was elaborated. The method is based on the transformation of ketones into the respective
enol acetates followed by photosensitized oxygenation. Methyl 7-oxo-11-homodrima-5,8-dien-12-oate, 5,6-dehydro-7-ketoisodrimenine,
11-acetoxydrima-5,8-dien-7-one and 11,12-diacetoxydrima-5,8-dien-7-one were prepared in high yields starting from methyl 7-oxo-11-homodrim-8-en-12-oate,
7-oxoisodrimenine, 11-hydroxydrim-8-en-7-one and 11,12-diacetoxydrim-8-en-7-one, respectively.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 678–682, April, 2006. 相似文献
15.
M. Chatelut S. Chah-Bouzziri O. Vittori A. Benayada 《Journal of Solid State Electrochemistry》2000,4(8):435-443
A lead electrode was studied in 6 and 12 M H3PO4. Oxidation of a freshly polished electrode occurred in the −0.5 to −0.3 V vs. SCE range, and led to PbHPO4 growth on the electrode surface. The dissolution of this layer by electrochemical reduction occurred between −0.5 and −0.7 V.
The influence of temperature (20 °C and 65 °C) was investigated and showed that the anodic and the cathodic peaks were increasing,
and more markedly for the 12 M H3PO4. The ratio Q
cathodic/Q
anodic (Q=electrical charge flowing through the electrode) was equal or close to the unity at 20 °C and decreased as the temperature
was increased. The influence of Cl−, Br− and I− ions was also evaluated. The addition of Cl− and Br− predominantly led to Pb5(PO4)3Cl and Pb5(PO4)3Br, respectively, while I− led to a mixture of PbI2 and PbHPO4.
Received: 18 July 1999 / Accepted: 2 November 1999 相似文献
16.
Concerning the preparation of 7-amino-cephalosporanic acid 总被引:1,自引:0,他引:1
7-Aminocephalosporanic acid or esters thereof are prepared either by intramolecular aminolysis of esters of the antibiotic cephalosporin C or vïa imino-ethers derived from the latter. A simple procedure for the preparation of 7-aminocephalosporanic acid in high yield is described. 相似文献
17.
The conformations of poly(l-glutamic acid) [P(Glu)] in solutions of the bipolar amphiphile 1,20-icosanediylbis(alkylammonium chloride) [C20(RA)2], where RA includes trimethylammonium (TMA), dimethylammonium (DMA), or methylammonium (MA), were investigated with measurements
of the circular dichroism spectra at 10–35 °C. All C20(RA)2 induced an α-helix of P(Glu) in the aqueous solutions. The residue molar ellipticity at 222 nm showed a similar dependence
on the amphiphile concentration (C
s) below 0.5 of the ratio of 2C
s to the residue concentration (C
p) of P(Glu), but it separated into three directions at 2C
s/C
p>0.5. C20(MA)2 induced an α-helix of P(Glu) at 2C
s/C
p<0.5 followed by a helix aggregate at 2C
s/C
p>0.5. C20(DMA)2 and C20(TMA)2 also induced an α-helix, but a helix aggregate. C20(TMA)2 indicated a strong temperature dependence and did not induce a complete α-helix at 35 °C.
Received: 20 June 2001 Accepted: 6 September 2001 相似文献
18.
《Analytical letters》2012,45(10):2265-2280
Abstract A simple and rapid enzymatic fluorimetric method for the determination of ursodeoxycholic acid (UDCA) and its glycine (GUDCA) and taurine (TUDCA) conjugates in urine has been developed. Octadecylsilane-bonded silica cartridges (Sep-Pak C18) are used for the solid-phase extraction of bile acids (BA) from urine samples. the method is based on the fluorimetric monitoring of NADPH formed via the reaction of 7β hydroxylated BA (7β-BA) with β-nicotinamide adenine dinucleotide phosphate (β-NADP+) catalysed by 7β hydroxysteroid dehydrogenase (7β-HSD). the 7β-HSD, which is not yet commercially available, was isolated from Clostridium absonum cultures (ATCC # 27555) and purified by affinity chromatography. The method has a limit of detection of 2 μmol/L (initial sample concentration), within-run precision varied from 8.3% to 5.3% and between-run precision varied from 12% to 1.8% for low and high concentrations respectively. the recovery of ursodeoxycholic acid added to urine samples was about 98% (range 88–110%). the method was successfully applied for UDCA determination in urine samples from patients subjected to UDCA therapy. Randomly collected urine samples from patients and controls were used and the results were expressed as ratio of [UDCA]/[creatinine] to correct for variation in urine flow. 相似文献
19.
Pascale Bénézeth Donald A. Palmer David J. Wesolowski 《Journal of solution chemistry》1997,26(1):63-84
The three molal dissociation quotients for citric acid were measured potentiometrically with a hydrogen-electrode concentration
cell from 5 to 150°C in NaCl solutions at ionic strengths of 0.1, 0.3, 0.6, and 1 molal. The molal dissociation quotients
and available literature data at infinite dilution were fitted by empirical equations in the all-anionic form involving an
extended Debye-Hückel term and up to five adjustable parameters involving functions of temperature and ionic strength. This
treatment yielded the following thermodynamic quantitites for the first dissociation equilibrium at 25°C: logK
1a=−3.127±0.002, ΔH
1a
o
=4.1±0.2 kJ-mol−1, ΔS
1a
o
=−46.3±0.7 J-K−1-mol−1, and ΔCp
1a
o
=−162±7 J-K−1-mol−1; for the second acid dissociation equilibrium at 25°C: logK
2a
=−4.759±0.001, ΔH
2a
o
=2.2±0.1, ΔS
2a
o
=−83.8±0.4, and ΔCp
2a
o
=−192±15, and for the third dissociation equilibrium at 25°C: logK
3a=−6.397±0.002, ΔH
3a
o
=−3.6±0.2, ΔS
3a
o
=−134.5±0.7, and ΔCp
3a
o
=−231±7. 相似文献
20.
Electromotive-force (emf) measurements of cells containing solutions of hydrochloric acid and neodymium chloride were reported
at constant total ionic strengths (I) of 0.01, 0.025, 0.05, 0.1, 0.25, 0.5, 1.0, and 1.5 mol-kg−1 at 11 temperatures ranging from 5 to 55 ∘C, and at I = 2.0 mol-kg−1 at 25 ∘C. Hydrogen and silver–silver chloride electrodes were used in these cells. Results from the emf measurements, the mean molal
activity coefficients of HCl in HCl + NdCl3 + H2O mixtures, as well as the Harned interaction coefficients using Harned's rule are reported in the preceding article in this
issue. The ion-interaction model of Pitzer is applied here for the evaluation of the Pitzer mixing coefficients, SθH,Nd and ψH,Cl,Nd, as well as the linear representation of the temperature derivatives of ∂SθH,Nd /∂ T and ∂ψH,Nd,Cl/∂T. The activity coefficients at several ionic strength fractions y of NdCl3 are given at 25 ∘C. The results are interpreted in terms of ionic interactions. 相似文献