青霉素合成新型头孢菌素中间体-GCLE研究

GCLE是合成头孢菌素药物的新型中间体。本文阐述了GCLE的研究意义,介绍了GCLE的国内外相关技术领域发展现状及其本研究方向。     

青霉素扩环合成头孢菌素的研究进展

论述了由青霉素扩环合成头孢菌素的目的和意义,介绍了研究进展情况,并对目前所采用扩环方法进行了评价;重点介绍了 C3取代甲基中间体,尤其是应用广泛的 C3卤代甲基中间体的合成。     

青霉素亚砜扩环制头孢菌素中间体的研究

头孢菌素是一类重要的抗生素,本文介绍了由青霉素扩环得到头孢母核的合成以及国内外研究方法及其进展。     

半合成青霉素、头孢菌素及其侧链

半合成青霉素和头孢菌素同属于β－内酰胺类抗生素。较重要的侧链─—左旋苯甘氨酸将会有很大的发展。     

半合成青霉素,头孢菌素及其侧链

半合成青霉素和头孢菌素同属于β－内酰胺类抗生素，较重要的侧链－左旋苯甘氯酸将会有很大的发展。     

头孢菌素及其相关应用研究新进展

头孢菌素类抗生素是临床常用的一类十分重要的抗菌药。基于检索和分析国内外相关文献,归纳出近几年头孢类抗生素的研究新动向:新型检测发现,对血清特异性IgE抗体与头孢菌素-人血清白蛋白结合过程的监测,是一项敏化检测的重要指标。突变学研究发现,氧亚氨基取代类头孢菌素特异性荧光标记,可有效监测这种结构诱导性形变。新型头孢菌素CXA-101的相关研究、新生儿头孢菌素类药代动力学研究、毒理学及耐药性问题的较新研究,都可以为头孢类项目研究提供思路,从而推动头孢类抗生素研究与生产的发展。     

头孢菌素类抗生素发展与研究概况

文章介绍了头孢菌素类抗生素的发展概况,阐述了当前该类抗生素的研究进展、特点、方向及趋势。     

头孢菌素中间体GCLE的合成及应用

本文介绍了GCLE的合成路线和化学特性。以青霉素G为起始原料 ,将它的酯氧化物经热解开环、氯化、闭环制得GCLE。我国对工艺进行优化 ,目前也有GCLE的批量生产。生产成本在 10 0 0元 /kg左右 ,产品纯度95 %。由于GCLE中C3位氯甲基具有化学活泼性 ,因此可以从GCLE方便地制得各种新型头孢类抗生素     

青霉素制备青霉素亚砜的研究

以青霉素G钾盐与低质量分数过氧乙酸为原料氧化制备青霉素亚砜 ,其最佳工艺条件为 :n(C16 H18N2 O4 SK)∶n(CH3CO3H) =1 .0∶( 1 1～ 1 2 ) ,反应温度 0～ 5℃ ,反应时间 2 .0～ 2 5h ,w(CH3CO3H) =8 5% ,w(CH3CO2 H) =1 0 %。青霉素亚砜收率达 96 8%。同时建立了青霉素亚砜的半定量分析方法 ,以硅胶G为固定相 ,以V(CH3CO2 C4 H9 n)∶V(CH3CO2 H)∶V(NaH2 PO4 -H2 O)∶V(C4 H9OH n) =6.0∶2 .0∶1 .0∶0 5为流动相 ,用TLC法对产品进行半定量分析检测 ,并经IR、MS谱图验证了产品结构。     

青霉素酰化酶的生产与应用新进展

介绍了青霉素酰化酶的生产及应用新进展。着重介绍了青霉素酰化酶固定化技术的发展。青霉素酰化酶主要应用于6氨基青霉烷酸的工业生产和半合成的β内酰胺抗生素的合成,是在半合成抗生素的生产上有重要作用的一种酶。此外,青霉素酰化酶也可应用于其它的生物转化,如肽的合成、手性化合物的外消旋混合物的拆分。     

头孢菌素C发酵液可压缩性及膜分离的工艺研究

研究头C发酵液,确定头C发酵液具有一定的可压缩性,可压缩性指数在0．30～0．45之间。提出有效透膜压差的概念,认为膜通量与有效透膜压差成正比,对膜通量分析有积极作用。进一步探讨发酵液可压缩性对膜分离的影响,得出结论：可压缩性指数越小,有效透膜压差和透过通量越大,越有利于膜分离过程。     

头孢菌素C的分离研究进展

通过分析头孢菌素C发酵液的特点,论述传统分离过程,同时介绍了新技术膜过滤的应用情况并与传统的工艺进行比较,指出未来膜技术在分离头孢菌素C中有广阔的应用前景.     

头孢中间体GCLE的研究开发进展

综述了 7 苯乙酰胺 3 氯甲基头孢烷烯酸对甲氧基苄酯 (GCLE)的三种合成路线。并介绍了GLCE的用途。     

涂装前处理的发展方向及新技术研究

介绍了涂装前处理的前景及目前的主要新技术。     

头孢活性酯生产废液中回收三苯基氧膦和2-巯基苯并噻唑

研究了从头孢活性酯生产的废液中回收三苯基氧膦（TPPO）和2-巯基苯并噻唑（M）的方法,探讨了各种条件对回收率的影响。结果表明。室温下往头孢活性酯的生产废液中加入w（NaOH）=4％的溶液,调节pH至10-11,分层。水层在60℃下滴加w（HCl）=15％的稀盐酸,调节pH至2-3,过滤得M,回收率达95％;有机层减压浓缩至干。所得固体残渣用甲苯重结晶,得TPPO,回收率达90％。M和TPPO的纯度（HPLC）均在98．5％以上,因此．本工艺具有工业化应用前景。     

Types and Functions of Mitoribosome-Specific Ribosomal Proteins across Eukaryotes

Mitochondria are key organelles that combine features inherited from their bacterial endosymbiotic ancestor with traits that arose during eukaryote evolution. These energy producing organelles have retained a genome and fully functional gene expression machineries including specific ribosomes. Recent advances in cryo-electron microscopy have enabled the characterization of a fast-growing number of the low abundant membrane-bound mitochondrial ribosomes. Surprisingly, mitoribosomes were found to be extremely diverse both in terms of structure and composition. Still, all of them drastically increased their number of ribosomal proteins. Interestingly, among the more than 130 novel ribosomal proteins identified to date in mitochondria, most of them are composed of a-helices. Many of them belong to the nuclear encoded super family of helical repeat proteins. Here we review the diversity of functions and the mode of action held by the novel mitoribosome proteins and discuss why these proteins that share similar helical folds were independently recruited by mitoribosomes during evolution in independent eukaryote clades.     

蛋白质沉淀结晶研究进展

论述了国内外生物大分子 (蛋白质、酶等 )沉淀结晶的研究现状和进展 ,着重从结晶热力学、粒子聚集、结晶的成核与晶体生长 ,以及场的作用等方面阐述了蛋白质沉淀结晶过程的特定现象与可能的结晶机理 ,对蛋白质的沉淀结晶过程作了全面的描述 ,并提出未来研究方向 ,为蛋白质结构分析、新药设计、生化研究以及工业化生产提供一定的基础     

Penicillin-Binding Proteins, β-Lactamases,and β-Lactamase Inhibitors in β-Lactam-Producing Actinobacteria: Self-Resistance Mechanisms

The human society faces a serious problem due to the widespread resistance to antibiotics in clinical practice. Most antibiotic biosynthesis gene clusters in actinobacteria contain genes for intrinsic self-resistance to the produced antibiotics, and it has been proposed that the antibiotic resistance genes in pathogenic bacteria originated in antibiotic-producing microorganisms. The model actinobacteria Streptomyces clavuligerus produces the β-lactam antibiotic cephamycin C, a class A β-lactamase, and the β lactamases inhibitor clavulanic acid, all of which are encoded in a gene supercluster; in addition, it synthesizes the β-lactamase inhibitory protein BLIP. The secreted clavulanic acid has a synergistic effect with the cephamycin produced by the same strain in the fight against competing microorganisms in its natural habitat. High levels of resistance to cephamycin/cephalosporin in actinobacteria are due to the presence (in their β-lactam clusters) of genes encoding PBPs which bind penicillins but not cephalosporins. We have revised the previously reported cephamycin C and clavulanic acid gene clusters and, in addition, we have searched for novel β-lactam gene clusters in protein databases. Notably, in S. clavuligerus and Nocardia lactamdurans, the β-lactamases are retained in the cell wall and do not affect the intracellular formation of isopenicillin N/penicillin N. The activity of the β-lactamase in S. clavuligerus may be modulated by the β-lactamase inhibitory protein BLIP at the cell-wall level. Analysis of the β-lactam cluster in actinobacteria suggests that these clusters have been moved by horizontal gene transfer between different actinobacteria and have culminated in S. clavuligerus with the organization of an elaborated set of genes designed for fine tuning of antibiotic resistance and cell wall remodeling for the survival of this Streptomyces species. This article is focused specifically on the enigmatic connection between β-lactam biosynthesis and β-lactam resistance mechanisms in the producer actinobacteria.     

Vitamin K-Dependent Proteins in Skeletal Development and Disease

Vitamin K and Vitamin K-dependent proteins (VKDPs) are best known for their pivotal role in blood coagulation. Of the 14 VKPDs identified in humans to date, 6 play also important roles in skeletal biology and disease. Thus, osteocalcin, also termed bone Gla-protein, is the most abundant non-collagenous protein in bone. Matrix Gla protein and Ucma/GRP on the other hand are highly abundant in cartilage. Furthermore, periostin, protein S, and growth arrest specific 6 protein (GAS 6) are expressed in skeletal tissues. The roles for these VKDPs are diverse but include the control of calcification and turnover of bone and cartilage. Vitamin K plays an important role in osteoporosis and serum osteocalcin levels are recognized as a promising marker for osteoporosis. On the other hand, matrix Gla protein and Ucma/GRP are associated with osteoarthritis. This review focuses on the roles of these three VKDPs, osteocalcin, matrix Gla protein and Ucma/GRP, in skeletal development and disease but will also summarize the roles the other skeletal VKDPs (periostin, protein S and GAS6) in skeletal biology.     

新型抗冻剂-不冻蛋白质的研究与发展前景

不冻蛋白质(Ice Structuring Proteins,简称ISP)也称冻结构蛋白,是一种新型的抗冻剂,其具有抑制冰结晶生长的作用,包括抑制重结晶,同时还具有影响冰晶组织结构的作用。迄今为止科学工作者已从陆地昆虫、植物、细菌和真菌等各类生物中分离到多种抗冻蛋白,不冻蛋白质可以应用于冷冻食品工业、农业种植、医学等领域。本文简要地介绍了不冻蛋白质的性质、起源及研发历程、应用及发展趋势。