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排序方式: 共有96条查询结果,搜索用时 78 毫秒
81.
《Analytical letters》2012,45(11):2229-2244
ABSTRACT Penicillin-binding proteins (PBPs) were shown to associate non-covalently with many other morphogene proteins (MGPs). Specific associations were assigned. The PBPs were labeled with spectroscopic/fluorescence (F/S) groups in the form of dansylated β-lactam probes. Competitive β-lactam binding of non-denatured PBP/MGP complexes led to characteristic patterns of F/S labeling by the probes. The salt-bridge specific reagent, ethanedinitrile, covalently linked various MGPs to the F/S labeled PBPs. Proteolysis of chromatographically purified F/S labeled fractions gave sets of peptides analyzed by MALDI-TOF to give MH data. Peptide mass-fingerprinting analysis revealed that covalent linkage occurred with other MGPs and not with non-MGP proteins of ~3400 proteins in the SWISS-PROT r33 data base for E. coli K-12. 相似文献
82.
建立了同时检测全血中青霉素G及其2种主要代谢产物青霉噻唑酸和脱羧青霉噻唑酸的超高效液相色谱-电喷雾串联质谱分析方法。血样经简单的蛋白沉淀提取后,目标化合物经BEH C18色谱柱(50 mm×2.1 mm, 1.7 μm),以含0.1%甲酸溶液-乙腈为流动相,梯度洗脱分离后,选用正离子电喷雾多反应监测(MRM)模式检测。方法检出限(信噪比(S/N)为3计)为0.1~2.0 ng/mL,定量限(S/N=10)为0.5~5.0 ng/mL。各被测物的线性相关系数均大于0.9974,准确度为92.3%~105.5%,日内精密度小于10%。考察了不同储存温度(18、4、-18、-80 ℃)下全血中青霉素G及其代谢物的稳定性,结果表明随着储存温度升高和时间的延长,青霉素G的质量浓度下降明显。应用建立的方法检测了给予20 mg/kg青霉素G后的大鼠血液样本,血液中青霉素G原形药物在给药后0.5 h即消除完全(低于检出限),而其代谢物的体内消除时限可延长至36 h。所建方法对司法鉴定的适用性得到了进一步扩大,同时对食品残留检测也具有一定的参考价值。 相似文献
83.
84.
Poly(GMA/MA/MBAA) Copolymer Beads: a Highly Efficient Support Immobilizing Penicillin G Acylase 总被引:3,自引:0,他引:3
Ping XUE Guan Zhong LU Wan Yi LIU 《中国化学快报》2006,17(1):129-132
With development of the modern genetic engineering, enzymes can be produced in large quantities, and enzyme biocatalysts have been used more and more widely in the production of fine chemicals, drug and food products in recent years. Since the free enzyme… 相似文献
85.
Ke Li Monier Alhadi Abdelrahman Mohammed Yongshan Zhou Hongyi Tu Jiachen Zhang Chunli Liu Zhenbin Chen Robert Burns Dongdong Hu Juan M. Ruso Zhenghua Tang Zhen Liu 《先进技术聚合物》2020,31(3):368-388
Immobilized penicillin G acylase (PGA) as an important industrial catalyst can catalyze penicillin G potassium (PG) to 6‐aminopenicillanic acid (6‐APA). 6‐APA is an important intermediate for semisynthetic penicillin drugs, which occupies a huge market space in the anti‐inflammatory field; as a result, immobilized PGA occupies a huge market space in the pharmaceutical field. However, at present, there are different degrees of defects in the preparation and production process of immobilized PGAs on the market because of the huge demand; therefore, the performance of immobilized PGA and its productivity will bring huge economic benefits to enterprises. Therefore, research on immobilized PGA has always been a focus. This review first introduces the source, classification, structure, and catalytic mechanism of PGA and then studies the development of immobilization methods, immobilized carriers, reaction media, enzyme activity regeneration, and reactors of immobilized PGA in recent years. 相似文献
86.
87.
Amanda C FergusonRobert M Adlington Domnic H MartyresPeter J Rutledge Andrew CowleyJack E Baldwin 《Tetrahedron》2003,59(41):8233-8243
A route has been developed which allows synthesis of novel cyclobutanone analogues of penicillin. This is illustrated by the synthesis of (1R,4R,5R,5′R,7S)-(1b) and (1S,4S,5S,5′R,7R)-7-[5′-amino-5′-carboxy]pentanamido]-2-thiabicyclo[3.2.0]heptan-6-one-4-carboxylate (1a), an analogue of penicillin N. The key steps in the synthesis were the formation of the bicyclic structure via a [2+2] cycloaddition and the introduction of nitrogen at C7 via an intramolecular nitrene insertion. 相似文献
88.
Jesús Torres-Bacete Miguel Arroyo Raquel Torres-Guzmán Isabel de La Mata Carmen Acebal M. Pilar Castillón 《Applied biochemistry and biotechnology》2005,126(2):119-131
The culture medium for Streptomyces lavendulae ATCC 13664 was optimized on a shake-flask scale by using a statistical factorial design for enhanced production of penicillin
acylalse. This extracellularenzyme recently has been reported to bea penicillin Kacylase, presenting also high hydrolytic
activity against penicillin V and other natural aliphatic penicillins such as penicillin K, penicillin F, and penicillin dihydroF,.
The factorial design indicated that the main factors that positively affect penicillin acylase production by S. lavendulae were the concentration of yeast extract and the presence of oligoelements in the fermentation medium, whereas the presence
of olive oil in the medium had no effect on enzyme production. An initial concentration of 2.5% (w/v) yeast extract and 3
μg/mL of CuSO4·5H2O was found to be best for acylase production. In such optimized culture medium, fermentation, of the microorganism yielded
289 IU/L of enzyme in 72 h when employing a volume medium/volume flask ratio of 0.4 and a 300-rpm shaking speed. The presence
of copper, alone and in combination with other metals, stimulated biomass as well as penicillin acylase production. The time
course of penicillin acylase production was also studied in the optimized medium and conditions. Enzyme production showed
catabolite repression by different carbon sources such as glucose, lactose, citrate, glycerol, and glycine. 相似文献
89.
90.
反相高效液相法测定空气氧化青霉素衍生物反应的转化率 总被引:2,自引:0,他引:2
在空气氧化青霉素衍生物合成亚砜的反应中 ,用溶胶 凝胶法包容催化剂乙酰丙酮钴 (Ⅲ ) ,使反应在非均相条件下进行。采用反相高效液相法测定了该反应的转化率。采用的柱为C1 8反相柱 (4 6mmi d × 1 50mm ,1 0 μm) ,流动相为甲醇 水 (体积比为 85∶1 5)溶液。在 2 70nm检测波长下 ,青霉素G 对甲氧基苄基酯亚砜(PGPMBO)检测量在 0 0 5g·L- 1 ~ 0 40g·L- 1 时 ,与其峰面积具有良好的线性关系 ,线性相关系数为 0 9992。在不同反应条件下反应的最高转化率为 98 8%。该方法可直接对反应体系进行测定 ,可以快速准确地测定出反应的转化率 。 相似文献