首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到19条相似文献,搜索用时 390 毫秒
1.
L-山梨糖脱氢酶的纯化及性质的研究   总被引:2,自引:0,他引:2  
从5L罐发酵L-山梨糖的Gluconobacter SCB329和Bacillus thuringiensis SCB933混合菌株中差速离心收集SCB329菌体,破碎,离心获得无细胞抽提液,硫酸铵分级沉淀蛋白后依次经DEAECellulose 52和Q Sepharose FF柱层析分离得到了L-山梨糖脱氢酶(SDH),它能将L-山梨糖脱氢氧化为L-山梨酮,SDS-PAGE电泳测得分子量约为60KD。动力学性研究表明它为一个典型的Michaelis-Menten氏酶,对L-山  相似文献   

2.
从农药厂废水中分离到6株能以除草剂阿特拉津为唯一氮源生长的细菌,即假单胞菌(Pseu-domonas spp.)AD1、AD2和 AD6,土壤杆菌(Agrobacterium sp.)AD4,黄单胞菌(Xanthomonas sp.)ADS,欧文氏菌(Erwinia sp.)AD7。AD1菌株能使无机盐培养基中的 0.3g/L阿特拉津在72h内降解99,9%。当以AD1、AD2、AD4、AD5、AD6和AD7菌株的总DNA为模板进行PCR扩增时,除A  相似文献   

3.
地衣芽孢杆菌(Bacilluslicheniformis)NK-27菌株发酵产生的β-甘露聚糖酶(βmannanase)经硫酸铵盐析沉淀,两次DEAE纤维素和SephadexG-100离子交换柱层析以及制备PAGE筹步骤,获得了凝胶电泳均一的样品。用SDS-凝胶电泳测得纯化后的β-甘露聚糖酶分子量为26kD,用凝胶聚焦电泳测得等电点PI为5.0。酶反应的最适pH为9.0,最后温度为60℃,稳定pH为6.0—9.0,稳定温度为40℃。金  相似文献   

4.
本文介绍了用微结晶纤维素簿板层析对小单孢菌(Micromonospora)细胞壁中二氨基庚二酸(DAP)异构体及其3-羟基衍生物(3-OHDAP)进行快速分析的方法。在甲醇:水:冰乙酸:吡啶(10:5:0.25:1)的溶剂系统中测得RLL-DAP:meso-DAP为0.88,DD-DAP为0.78,3-OHDAP为0.72。  相似文献   

5.
从2-酮基-D-葡萄糖酸产生菌荧光假单胞菌K1005的异学发酵液中分离到两种噬菌体,分别将其命名为KS502和KS503。电镜观察表明KS502呈微球形,直径为61nm;KS503呈蝌蚪形,具有直径为68nm的六角形头部及85nm长的尾部。利用紫外线诱变的方法,经多次分离筛选,获得了2株抗性稳定且产酸水平超过对照敏感菌的抗噬菌体菌株,可以应用于生产。  相似文献   

6.
Metylomonassp.GYJ3菌的甲烷单加氧酶(MMO)粗酶提取液经DEAE-SepharoseCL-6B阴离子交换层析、SephadexG-100凝胶过滤层析和DEAE-TSKgelHPLC分离纯化出MMO还原酶组分.经HPLC分析,纯度大于95%,纯化倍数为4.4,加入至MMO羟基化酶和调节蛋白B的体系中表现比活为228nmol环氧丙烷每分钟毫克蛋白.SDS-PAGE电泳表明还原酶由一种亚基组成,分子量42kD.ICP-AES测定还原酶的Fe含量为1.83molFe每mol蛋白.UV-Vis光谱表明还原酶除280nm蛋白质特征峰外在460nm有最大吸收峰,且A280nm/A460nm为2.50,与其它黄素一铁硫蛋白相似,推测还原酶可能含一个FAD辅基和Fe2S2中心.在厌氧条件下,还原酶能够和NADH作用,UV-Vis光谱分析表明还原酶460nm处特征吸收峰消失,说明在MMO催化过程中还原酶接受NADH的电子.DEAE-SepharoseCL-6B阴离子交换层析分离出调节蛋白B,部分纯化的调节蛋白B的分子量大约在20kD,它能够提高MMO比活性40倍,MMO还原酶和调节蛋白B单独存在时不具有MMO  相似文献   

7.
S-921抗生素效价的化学测定法   总被引:1,自引:0,他引:1  
S-921抗生素由金色链霉菌(Streptomycesaureus)S-921菌株产生,它在304nm处有极大吸收峰,以304nm处的吸光度A对浓度(效价)C进行线性回归,当吸光度A在0.040-0.820范围内时,得回归方程为:C=123.64A-2.651,经检验线性回归关系极显著,可用紫外分光光度法测定其效价。  相似文献   

8.
拮抗菌BS—98分泌抗菌蛋白的条件及其发酵液特性   总被引:7,自引:2,他引:5  
由本室分离得到一株强烈抑制芦笋茎枯病等植物病原真菌的拮抗菌BS—98菌株(Bacillussubtilis)。用环柱法检测该菌株的抗菌活性表明,该菌株除抑制芦笋茎枯病菌PhomaasparagiSacc外,对小麦赤霉病菌(Fusariumgraminearum),棉花枯萎病菌(Fusariumoxysporumfsp.Vasinfectum)、棉花黄萎病菌(Verticillumalbo—atrum)、黄瓜灰霉病菌(Botryti  相似文献   

9.
苏云金杆菌(Bacillus thuringiensis)9165超氧化物歧化酶(SOD),经硫酸铵分级沉淀、SephadexF-100凝胶过滤及非变性凝胶电泳(PAGE)三步纯化,纯酶比活力为4388u/mg,属Mn-SOD,分子量为47.9ku,由二个亚基组成,含19种氨基酸。  相似文献   

10.
L—山梨糖脱氢酶的纯化及性质的研究   总被引:12,自引:2,他引:10  
从5L罐发酵L-山梨糖的Gluconibacter oxydans SCB329和Bacillus thuringiensis SCB933混合菌株中差速离心收集SCB329菌体,破碎,离心获得无细胞抽提液,硫酸铵分级沉淀蛋白后依次经DEAE Cellulose 52和Q Sepharose FF柱层析分得到了L-册梨糖脱氢酶(SDH),它能将L-册梨糖脱氢氧化为L-册梨酮,SDS-PAGE电泳测  相似文献   

11.
12.
13.
Microbial processes for ascorbic acid biosynthesis: a review.   总被引:1,自引:0,他引:1  
L-Ascorbic acid is an important product currently made using the Reichstein process, which is mainly chemical. Recently, bacteria have been identified that are able to transform in a very efficient way glucose to 2,5-keto-D-gluconic acid and this product to 2-keto-L-idonic acid, precursor of L-ascorbic acid. When the corresponding strains are used together, it is possible to get 2-keto-L-idonic acid directly from glucose. Moreover, new strains have been constructed by introducing a gene from a strain responsible for the second step into a strain responsible for the first step. By using one of the new strains, the transformation can be performed in a single step with only one strain. However, the classical process still remains the most competitive.  相似文献   

14.
Antibodies with enzymatic activity were named abzymes or catalytic antibodies. In the present study, the lipolytic abzymes were selected from the phage displayed antibody libraries against a transition state analog (TSA) of lipases/esterases. After three rounds of selection, four monoclonal phage particles capable of binding significantly with the TSA were obtained. The soluble scFv antibody fragments were further expressed and obtained using Escherichia coli strain HB2151. The binding capabilities and the apparent enzymatic activities of the purified antibody proteins were measured. The 3D structures of the expressed antibodies were also predicted through homology modeling and binding-site prediction algorithm. The present method demonstrates that selection from phage displayed antibody libraries is an efficient and convenient means to find new abzymes.  相似文献   

15.
目的:利用噬菌体展示技术构建抗脐带间充质干细胞表面分子噬菌体ScFv抗体库。方法:收集P3代培养的UC-MSCs免疫BALB/c小鼠,提取其脾细胞总RNA,RT-PCR扩增全套VH和VL基因片段,将其先后克隆入噬菌粒pSEX81中,构建成完整的噬菌体ScFv抗体库。结果:构建的噬菌体ScFv抗体库的库容为2×107cfu,ScFv插入重组率为93%,BstN1酶切图谱呈不同多样性。ScFv抗体库经3轮初步筛选后插入重组率达100%,3个克隆出现了相同的酶切图谱,并且随着筛选次数的增加,输出/输入比明显提高,这说明抗体库得到了特异性富集。结论:成功地构建了抗脐带间充质干细胞表面分子噬菌体ScFv抗体库,这为将来筛选特异性抗体和进一步用于间充质干细胞表面特异性分子研究奠定了坚实的基础。  相似文献   

16.
K Jarrell  A M Kropinski 《Microbios》1977,19(76):103-116
The chemical composition of the lipopolysaccharide (LPS) of the smooth strain Pseudomonas aeruginosa PAO 307 and a spontaneously derived rough mutant, obtained by selection for resistance to the LPS-specific phage E79, are compared. The rough LPS was shown to contain lipid A, heptose, 2-keto 3-deoxyoctonic acid, galactosamine, alanine and phosphate but lacked glucose, rhamnose and fucosamine which were important constituents, on a weight basis, of the smooth LPS. These results, and chromatographic analysis of the polysaccharide fraction indicate that the rough strain lacked side chain material and was defective in its inner core region. The chemical date obtained were consistent with a core in the PAO strain similar to that of strain NCTC 1999, enhancing the evidence for a common core polysaccharide in the LPS of P. aeruginosa strains.  相似文献   

17.
Threonyl-transfer ribonucleic acid synthetase (ThrRS) has been purified from a strain of Escherichia coli that shows a ninefold overproduction of this enzyme. Determination of the molecular weight of the purified, native enzyme by gel chromatography and by polyacrylamide gel electrophoresis at different gel concentrations yielded apparent molecular weight values of 150,000 and 161,000, respectively. Polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate yields a single protein band of 76,000-dalton size. From these results an alpha(2) subunit structure can be inferred. A mutant with a structurally altered ThrRS, which had been obtained by selection for resistance against the antibiotic borrelidin, was used to map the position of the ThrRS structural gene (thrS) by P1 transductions. It was found that thrS is located in the immediate neighborhood of pheS and pheT, which are the structural genes for the alpha and beta subunits of phenylalanyl-transfer ribonucleic acid (tRNA) synthetase, the gene order being aroD-pheT-pheS-thrS. A lambda phage that was previously shown to specifically transduce pheS, pheT, and also the structural gene for the translation initiation factor IF3 can complement the defect of the altered ThrRS of the borrelidin-resistant strain. This phage also stimulates the synthesis of the 76,000, molecular-weight polypeptide of ThrRS in ultraviolet light-irradiated. E. coli cells. These results indicate that the genes for ThrRS, alpha and beta subunits of phenylalanyl-tRNA synthetase, and initiation factor IF3 are immediately adjacent on the E. coli chromosome.  相似文献   

18.
Antimicrobial peptides were isolated from a phage display peptide library using bacterial magnetic particles (BacMPs) as a solid support. The BacMPs obtained from “Magnetospirillum magneticum” strain AMB-1 consist of pure magnetite (50 to 100 nm in size) and are covered with a lipid bilayer membrane derived from the invagination of the inner membrane. BacMPs are easily purified from a culture of magnetotactic bacteria by magnetic separation. Approximately 4 × 1010 PFU of the library phage (complexity, 2.7 × 109) was reacted with BacMPs. The elution of bound phages from BacMPs was performed by disrupting its membrane with phospholipase D treatment. Six candidate peptides, which were highly cationic and could bind onto the BacMP membrane, were obtained. They exhibited antimicrobial activity against Bacillus subtilis but not against Escherichia coli and Saccharomyces cerevisiae. The amino acid substitution of the selected peptide, KPQQHNRPLRHK (peptide 6-7), to enhance the hydrophobicity resulted in obvious antimicrobial activity against all test microorganisms. The present study shows for the first time that a magnetic selection of antimicrobial peptides from the phage display peptide library was successfully achieved by targeting the actual bacterial inner membrane. This BacMP-based method could be a promising approach for a high-throughput screening of antimicrobial peptides targeting a wide range of species.  相似文献   

19.
A continuous conversion process of rice starch hydrolysate to 2-keto-D-gluconic acid (2KGA) by Arthrobacter globiformis C224 was developed. Its feasibility for industrial application was also evaluated. Results showed that the initial cell concentration exceeding 1.25 g/L met the continuous 2KGA production at a stable dilution rate and media composition, while the dilution rate and feeding glucose concentration had a significant effect on 2KGA production performance. The optimal operating parameters were obtained as: 0.090/h of dilution rate and 171.0 g/L of feeding glucose concentration. Under these conditions, the steady state had a produced 2KGA concentration of 124.74 g/L, average volumetric productivity of 11.23 g/L/h, and yield of 0.97 g/g. In conclusion, continuous 2KGA production by the A. globiformis C224 strain would be a superior industrial process for the production of 2KGA in terms of its high 2KGA productivity and yield.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号