共查询到20条相似文献,搜索用时 15 毫秒
1.
Summary A microfermentation procedure was employed to determine the effects of peptones on the growth ofPaecilomyces
persicinus P-10 M1 and its synthesis of cephalosporin C. Of the peptones tested only papain digest of soy peptone supported the production of cephalosporin C byP.
persicinus P-10 M1. 相似文献
2.
Summary A process for the production (in a stirred tank reactor) of glutaryl-7-ACA from cephalosporin C using immobilized D-amino acid oxidase is described. Results so obtained under optimal conditions (1.2 mg coupled enzyme/L, pH 8.5, 2 mM cephalosporin C) point to a system which shows high conversion efficiency and a remarkable operational stability. No exogenous H2O2 is requested to shift the reaction equilibrium toward glutaryl-7-ACA production, nor any side product is detected. The immobilized system productivity was 54 g/day/mg of enzyme. This process represents the first reported case of a reactor successfully developed with a DAAO for bioconversion of cephalosporin C. 相似文献
3.
Affinity chromatography purification of penicillinase of Bacillus licheniformis 749-C and its use to measure tuurnover of the cell bound enzyme 总被引:5,自引:0,他引:5
L J Crane G E Bettinger J O Lampen 《Biochemical and biophysical research communications》1973,50(2):220-227
Affinity chromatography purification of small amounts of penicillinase using cephalosporin C covalently linked to Sepharose 4B has been used in examining the turnover of cell-bound penicillinase by B. licheniformis 749/C. Under conditions in which most of the nascent penicillinase is retained by the cells, turnover could be demonstrated (15% of the cell-bound enzyme in 2.5 hours), although most of the secreted enzyme is derived from newly-formed molecules. 相似文献
4.
Summary Caprolactam, butan-2-one, butan-2-ol, and butan-1, 3-diol were found to have a stimulating effect on the biosynthesis of cephalosporin C by a mutant strain ofCephalosporium. Caprolactam was shown to have a synergistic effect, when added to the fermentation medium together with each of the other three compounds. 相似文献
5.
Summary
Trichoderma reesei Rut-C30 was found to produce extracellular lactase when grown on lactose medium. Maximum enzyme levels in continuous culture were observed at dilution rates (D) between 0.02 and 0.027 hr-1. The enzyme productivity reached 27.3 U/L hr at D = 0.027 hr-1. Lactase synthesis appears to be inducible and subject to catabolite repression. Optimal growth temperature and pH for enzyme production were 28°C and pH 5. Maximum enzyme activity was observed at 63°C and pH 4.6. The apparent Km, based on the nitrophenyl-galactopyranoside assay was estimated as 0.4 mM. The enzyme is suitable for lactose hydrolysis in acid whey. 相似文献
6.
Pierre Borgeat Bernard Fruteau de Laclos Serge Picard Jean Drapeau Pierre Vallerand E. James Corey 《Prostaglandins & other lipid mediators》1982,23(5):713-724
Incubation of peripheral blood leukocytes with arachidonic acid (and ionophore A23187) led to the formation of leukotriene B4, Δ6-trans-leukotriene B4, Δ6-trans-12-epi-leukotriene B4, 5-hydroxy-icosatetraenoic acid, 12-hydroxy-icosatetraenoic acid and of 5S,12S-dihydroxy-6,8,10,14-(E,Z,E,Z)-icosatetraenoic acid (5S,12S-DiHETE). Incubation of leukocytes with leukotriene A4 resulted in the formation of leukotriene B4 and of its two Δ6-trans-isomers but not of the 5S,12S-DiHETE. 18O2 labeling experiments have shown that the hydroxyl groups at C5 and C12 in the 5S,12S-DiHETE are derived from molecular oxygen. The tetraacetylenic analog of arachidonic acid was found to be a potent inhibitor of the formation of the 5S,12S-DiHETE whereas it potentiated the synthesis of the 5-hydroxy acid and of leukotriene B4. Addition of the 12-hydroxy-icosatetraenoic acid to leukocytes, or of the 5-hydroxy-icosatetraenoic acid to a suspension of platelets caused the formation of the 5S,12S-DiHETE. It is concluded that the 5S,12S-DiHETE is not derived from leukotriene A4 but is a product of the successive reactions of arachidonic acid with two lipoxygenases of different positional specificities. 相似文献
7.
M. J. Lancaster R. J. Sharp J. R. Court I. D. McEntee R. G. Melton R. Sherwood 《Biotechnology letters》1989,11(10):699-704
Summary The optimum production of cloned carboxypeptidase G2 from plasmid pNM21 byEscherichia
coli was found to be strongly strain- and temperature-dependent. The superior host was strain RV308 and the preferred growth temperature 28°C. Copy number, which decreased during exponential growth of all strains examined, did not relate in these studies to the level of enzyme production: the strain with the highest enzyme yield also having the lowest overall copy number. 相似文献
8.
Cephalosporin was used to synthesize soluble and precipitating fluorogenic β-lactam substrates that demonstrated differential catalytic hydrolysis by three different subtypes of β-lactamase: TEM-1 (class A), p99 (class C), and a Bacillus cereus enzyme sold by Genzyme (class B). The most successful soluble substrate contained difluorofluorescein (Oregon Green 488) ligated to two cephalosporin moieties that, therefore, required two turnovers to produce the fluorescent Oregon Green 488 leaving group. The bis-cephalosporin modification was required so that the final reaction product was the Oregon Green 488 carboxylic acid rather than a less bright phenolic adduct of the dye. Hydrolysis in pH 5.5 Mes and pH 7.2 phosphate-buffered saline (PBS) buffers was similar, but in pH 8.0 Tris the hydrolysis rate nearly doubled. Activity of the β-lactamases on the various substrates was shown to depend highly on the linker between the cephalosporin and the fluorophore, with an allyl linker promoting faster turnover than a phenol ether linker. Measured Km values for dichlorofluorescein and difluorofluorescein cephalosporin substrates were approximately the same as Km values for penicillin G and ampicillin found in the literature (∼30–40 μM). 相似文献
9.
Summary A polygalacturonase from culture filtrates of a strain ofRhizopus
stolonifer was purified about 80 fold by ethanol precipitation, followed by ion exchange chromatography (CM-Sepharose 6B) and gel filtration (Sephadex G-100). The purified preparation was homogeneous when examined by PAGE. The enzyme is an endopolygalacturonase with an optimum catalytic activity at pH 5.0 and 45°C, and a molecular weight of 57,000±500 daltons. The activity was stimulated by Fe+++, Mg++, Co++, and inhibited by Mn++ and Zn++. The enzyme was stable in the pH range of 3.0 to 5.0. The purified enzyme was specific for nonmethoxylate polygalacturonic acid, with Km and Vmax values respectively of 0.19 mg/ml and 1.3 mol/g/min. In addition, this enzymatic preparation degraded pectic substances in organge peel. 相似文献
10.
Summary
Streptomyces cattleya and Streptomyces clavuligerus were found to form immobilized populations on cotton cloth. The resulting bacterial films were used as resident inocula in batch fermentations of thienamycin and cephalosporin C. During 20 cycles of 3-day batch fermentation, these antibiotics were produced at the constant yields. 相似文献
11.
Hideyuki Suzuki Professor Chiaki Yamada Kyoko Kijima Sayaka Ishihara Kei Wada Keiichi Fukuyama Hidehiko Kumagai 《Biotechnology journal》2010,5(8):829-837
Semisynthetic cephalosporins, the best-selling antibiotics worldwide, are derived from 7-aminocephalosporanic acid (7-ACA). Currently, in the pharmaceutical industrie, 7-ACA is mainly produced from cephalosporin C by sequential application of D -amino acid oxidase and cephalosporin acylase. Here we study the potential of industrially amenable enzyme γ-glutamyltranspeptidase from Bacillus subtilis for 7-ACA production, since the wild-type γ-glutamyltranspeptidase of B. subtilis has inherent glutaryl-7-aminocephalosporanic acid acylase activity with a kcat value of 0.0485 s-1. Its activity has been enhanced by site directed and random mutagenesis. The kcat/Km value was increased to 3.41 s-1 mM-1 for a E423Y/E442Q/D445N mutant enzyme and the kcat value was increased to 0.508 s-1 for a D445G mutant enzyme. Consequently, the catalytic efficiency and the turnover rate were improved up to about 1000-fold and 10-fold, compared with the wildtype γ-glutamyltranspeptidase of B. subtilis. 相似文献
12.
Summary A thermo-stable dehalogenase was demonstrated in the crude extracts fromPseudomonas sp (19S). The ability of the enzyme to catalyze the dehalogenation of various halogen-substituted organic acids was investigated and the highest activity was found with monochloroacetate. The enzyme followed Michaelis-Menten kinetics, and the Km for monochloroacetate was 0.2mM. Maximum activity was found at pH 10.5 and 60°C. The enzyme activity in the cell-free extract was unaffected by EDTA or by Mn, Zn, or Cu ions, but was dramatically reduced by HgCl2 (70%) and Pb (NO3)2 (80%). 相似文献
13.
Partial purification and characterization of a NADPH dependent tetrahydroalstonine synthase from Catharanthus roseus cell suspension cultures 总被引:1,自引:0,他引:1
A new enzyme was discovered which specifically hydrogenates the iminium form of cathenamine at position 21 to yield the heteroyohimbine alkaloid tetrahydroalstonine. The enzyme was partially purified (35-fold) from Catharanthus roseus cell suspension cultures. It was shown to use exclusively NADPH as reductant, the pH optimum is at 6.6, the temperature optimum at 30°C, the half life of the soluble enzyme preparation is 26 min at 37°C, and the molecular weight is 81 000 ± 3%. Evidence is presented for the occurrence of two distinct and different cathenamine reductases, one reducing the iminium form of this central intermediate to give tetrahydroalstonine, the other one reducing cathenamine to yield ajmalicine. Tetrahydroalstonine synthase was present in cell suspension cultures of C. ovalis, C. roseus, Picralima nitida, Rhazya stricta, and Vinca herbacea.
Dedicated to Prof. Dr. Franz Lingens on the occasion of his 60th birthday 相似文献
14.
B. S. Deshpande S. S. Ambedkar J. G. Shewale 《World journal of microbiology & biotechnology》1996,12(4):373-378
Aeromonas sp. ACY 95 produces constitutively and intracellularly a penicillin V acylase at an early stage of fermentation (12 h) and a cephalosporin C acylase at a later stage (36 h). Some penicillins, cephalosporin C and their side chain moieties/analogues, phenoxyacetic acid, penicillin V and penicillin G, enhanced penicillin V acylase production while none of the test compounds affected cephalosporin C acylase production. Supplementation of the medium with some sugars and sugar derivatives repressed enzyme production to varying degrees. The studies on enzyme formation, induction and repression, and substrate profile suggest that the cephalosporin C acylase and penicillin V acylase are two distinct enzymes. Substrate specificity studies indicate that the Aeromonas sp. ACY 95 produces a true cephalosporin C acylase which unlike the enzymes reported hitherto hydrolyses cephalosporin C specifically.The authors are with Research and Development, Hindustan Antibiotics Limited, Pimpri. Pune 411 018, India 相似文献
15.
Energy conservation in malolactic fermentation by Lactobacillus plantarum and Lactobacillus sake 总被引:1,自引:0,他引:1
A comparably poor growth medium containing 0.1% yeast extract as sole non-defined constituent was developed which allowed
good reproducible growth of lactic acid bacteria. Of seven different strains of lactic acid bacteria tested, only Lactobacillus plantarum and Lactobacillus sake were found to catalyze stoichiometric conversion of l-malate to l-lactate and CO2 concomitant with growth. The specific growth yield of malate fermentation to lactate at pH 5.0 was 2.0 g and 3.7 g per mol
with L. plantarum and L. sake, respectively. Growth in batch cultures depended linearly on the malate concentration provided. Malate was decarboxylated
nearly exclusively by the cytoplasmically localized malo-lactic enzyme. No other C4-dicarboxylic acid-decarboxylating enzyme activity could be detected at significant activity in cell-free extracts. In pH-controlled
continuous cultures, L. plantarum grew well with glucose as substrate, but not with malate. Addition of lactate to continuous cultures metabolizing glucose
or malate decreased cell yields significantly. These results indicate that malo-lactic fermentation by these bacteria can
be coupled with energy conservation, and that membrane energetization and ATP synthesis through this metabolic activity are
due to malate uptake and/or lactate excretion rather than to an ion-translocating decarboxylase enzyme. 相似文献
16.
Characterization of cross‐linked immobilized arylesterase from Gluconobacter oxydans 621H with activity toward cephalosporin C and 7‐aminocephalosporanic acid
下载免费PDF全文
![点击此处可从《Biotechnology progress》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Cross‐linked enzyme aggregates (CLEAs) were prepared from several precipitant agents using glutaraldehyde as a cross‐linking agent with and without BSA, finally choosing a 40% saturation of ammonium sulfate and 25 mM of glutaraldehyde. The CLEAs obtained under optimum conditions were biochemically characterized. The immobilized enzyme showed higher thermal activity and a broader range of pH and organic solvent tolerance than the free enzyme. Arylesterase from Gluconobacter oxydans showed activity toward cephalosporin C and 7‐aminocephalosporanic acid. The CLEAs had a Kcat/KM of 0.9 M?1/S?1 for 7‐ACA (7‐aminocephalosporanic acid) and 0.1 M?1/S?1 for CPC (cephalosporin c), whereas free enzyme did not show a typical Michaelis–Menten kinetics. © 2015 American Institute of Chemical Engineers Biotechnol. Prog., 32:36–42, 2016 相似文献
17.
Mesophyll protoplasts from leaves of aseptically grown shoot tips of Diplotaxis muralis were isolated (6.2–7.1×105 protoplasts/g fresh weight of tissue) using one step enzyme digestion. The protoplasts (71% viability) underwent divisions (4.2+0.1%) on plating in M8PS2 medium and ultimately formed calli with 0.45+0.03% plating efficiency. Plant regeneration could be achieved both through embryogenesis and organogenesis. The efficiency of plant regeneration through organogenesis was 9 times higher than embryogenesis. Forty eight out of 52 plants regenerated so far from 3 independent experiments were normal with respect to fertility and meiotic chromosomal behavior.Abbreviations BAP
6-benzylaminopurine
- GA3
Gibberellic acid
- A
Kao and Michayluk, 1981
- KM
Kao and Michayluk, 1975
- MK3
Modified K3
- M8P
Modified 8P
- MS
Murashige and Skoog, 1962
- NAA
1-naphthalene acetic acid
- PE
Plating efficiency 相似文献
18.
Summary Laccase was purified from culture broth ofPleurotus ostreatus mycelium. The enzyme was a single protein of Mr 59000, pI 2.9 and was active on o-diphenyl substrates. Amino acid composition and N-terminal sequence (15 residues) were determined. Polyclonal anti-laccase antibodies were obtained. 相似文献
19.
Two protein bands with strong esterase activity are present in broths of Nocardia lactamdurans MA4213 cultures. One of them shows cephalosporin C acetylhydrolase (CAH) activity. This activity is maximal at 48 h of growth
and shows a pattern of regulation slightly different from that of cephamycin production in medium supplemented with glucose
(166 mM), glycerol (326 mM) or ammonium chloride (60 mM). The CAH activity was purified to homogeneity by DEAE-Sepharose ion-exchange,
Sephadex G-75 gel filtration, and phenyl-Sepharose hydrophobic interaction chromatography. It showed a molecular mass of 72,100 Da.
The N-terminus of the protein was determined and showed the amino acid sequence GGAAPGGPGAHPLWLPAGKD. The enzyme showed K
m values of 7.0 mM and 8.3 mM for cephalosporin C and 7-aminocephalosporanic acid respectively but was not active on cephamycin
C.
Received: 17 December 1999 / Received revision: 22 February 2000 / Accepted: 25 February 2000 相似文献
20.
Dipicolinic acid, a known inhibitor of an enzyme (dihydrodipicolinic acid reductase) in the maize (Zea mays L.) lysine biosynthetic pathway, inhibits the growth of maize suspension and callus cultures. Inhibited cultures contain somewhat lower free lysine levels, but the inhibition of suspension culture growth was not reversible with simultaneous addition of L-lysine to the culture medium. It is concluded that dipicolinic acid does not act solely as an analog blocking lysine production. Dipicolinic acid thus appears to be unsuitable as a selection for maize tissue culture mutants with lysine overproduction.Abbreviations FW
fresh weight
- I50
inhibitor concentration at which cell growth is inhibited by 50%
- MS
Murashige and Skoog (1962) culture medium
- ZM
Black Mexican Zea mays suspension culture of Chourey and Zurawski (1981) 相似文献