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微生物酶拆分方法生产D-泛酸的手性中间体D-泛解酸内酯 总被引:13,自引:0,他引:13
筛选到一株产D-泛解酸内酯水解酶的串珠镰孢霉菌(Fusarium moniliforme SW-902)。产酶条件研究表明,用甘油作碳源,蛋白胨作氮源,初始pH8.0,温度26℃,摇瓶培养3d,产酶量最高。在60L和1000L发酵罐中通风发酵45-47h,产酶量为6-8g干菌体/L,D-泛解酸内酯水解酶酶活力达到0.87-0.92IU/g干菌体。该酶的最适反应温度为55℃,最适反应pH为7.0-7.5。在酶不对称水解泛解酸内酯过程中,对溶液加酶量5%-10%,底物浓度10%-20%,控制水解率20%-30%,水解效果最好。 相似文献
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研究了产酯酶微生物的筛选,包括筛选模型、酶活力检测方法及菌株的分布。对30多份土样以及实验室保存的菌种进行了大量的筛选,以添加三醋酸甘油酯、乳酸乙酯酯类物质对土样等样品富集,采用添加显色剂溴甲酚紫的快速简便平板显色法,观察水解变色圈直径和菌落直径的大小进行初筛。获得两者直径之比相对大的菌株174株,采用平板打孔检测法和摇瓶发酵比色法测酶活力相结合进行复筛,最终得到酯酶活力较高的24株菌株。就初筛和复筛方法及结果加以比较分析,复筛菌株做不同底物的酶活力检测,建立了一个有效、简便及快速的微生物酯酶的筛选模型。并对酯酶产生菌的立体选择专一性进行了初步考察。 相似文献
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为建立廉价、高效的普瑞巴林关键手性中间体生产工艺,经单因素优化和正交试验,确定了摩氏摩根菌CCTCC M 2011175最佳产酯酶培养基,组成(g/L)为葡萄糖15.0,牛肉膏7.0,Na2HPO41.0,Fe2(SO4)30.1,吐温-8010.0。优化后酯酶比酶活达到1 071.0 U/L,为出发培养基的2.5倍。以培养基优化后获得的摩氏摩根菌菌体为催化剂,立体选择性拆分外消旋2-羧乙基-3-氰基-5-甲基己酸乙酯水解,转化率达到45%,对映体过量值(e.e.)大于94%,为酶法生产普瑞巴林关键手性中间体奠定了良好基础。 相似文献
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采用垂直平板聚丙烯酰胺凝胶电泳方法跟踪测定了 10 羽优黄 380 商品蛋鸡血清酯酶的遗传表现型,结果表明:血清酯酶( Es1)的遗传表达具有明显的发育阶段差异性,开产前均为有带类型,并表现出遗传多态现象,开产后 Es1 酶带消失,表现为无活性 O 型⒚对 I S A B380 父母代 C D 母鸡的扩大抽样测定结果验证了上述的结论⒚由此我们推测,母鸡产蛋期 Es1 区无活性“ O 型”可能是基因表达在不同发育阶段调控(抑制)的结果,因此不存在“ Es1基因座位上决定 O 型的等位基因 Es1o ⒚ Es1 基因在开产前处于转录活跃状态,开产后基因转录就被抑制,以维持产蛋期母鸡体内所需较高的血脂水平⒚母鸡血清酯酶表达发育遗传学规律可能广泛存在于家禽各种群体之中⒚如果该推测成立的话,家鸡酯酶的生物合成就可能成为研究禽类基因表达和调控的理想模型⒚ 相似文献
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采用垂直平板聚丙烯酰胺凝胶电泳方法随机抽样了后备,初产和产蛋3个阶段的优黄2000肉种鸡血清酯酶的遗传多态性,结果表明:血清酯酶Es-1和Es-2均存在遗传多态现象,Es-1区检出2-3条多态性酶带,Es-2区仅有1条带,表型为带的有或无。 相似文献
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本文进一步实验显示处于生物素饥饿状态的白色念珠菌摄取生物素具可饱合性和特异性。从饱合曲线测算出主动摄入生物素的半数最大初速率(1/2Vmax)所需生物素浓度,即Km值为079±011(平均数±标准差,n=8);叠氮钠(5mMol/L)处理后,其Km值增到239±064μmMol/L(平均数±标准差,n=3)。生物素之结构同源分子,如脱硫生物素、生物胞素、甲基酯生物素和对硝基苯酯生物素等竞争性抑制其主动摄取生物素,但是2亚氨基生物素却完全无抑制作用。在生物素摄入充足的白色念珠菌(在含20nMol/L生物素的培养基中生长),生物素主要通过简单的弥散方式进入菌体内。由于血清中的生物素含量在pMol/L到几个nMol/L之间,白色念珠菌在体内可能通过主动摄取生物素机制满足其营养代谢需求。本研究为发展抗白色念珠菌新举措可能提供某种理论基础 相似文献
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以自筛选出的具有一定不对称拆分外消旋酮基布洛芬氯乙酯能力的野生菌Bacillus megaterium NK13为材料,通过构建其基因文库,筛选得到一个阳性克隆重组子pUC18-NK-HYD3。分析测序结果发现外源片段中包含一段完整的741 bp的开放阅读框,其编码的蛋白中含有酯酶的GXSXG保守序列。经在NCBI的BLAST系统中比对,证明该酯酶基因属于首次发现(GenBank Accession Number: GU143552)。将酯酶基因克隆到载体pET21b(+)中,转化E. coli BL21(DE3),经IPTG诱导后在宿主菌得到表达。SDS-PAGE电泳检测证明该酯酶蛋白分子量约为28 kDa。TLC和HPLC检测结果显示,该酯酶优先水解(R)-型底物,在重组菌菌液体系,转化率为15%时,酯酶拆分获得(R)-酮基布洛芬的过量值(e.e.%)最高,达62.74%;改用重组菌湿菌体的PBS体系后,在转化率为10%~50%时,酯酶拆分获得(R)-酮基布洛芬的过量值(e.e.%)一直保持在73%~76%之间。 相似文献
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The new lines Nanhua 5, Nanhua 11, Shanyou 39, and Shanyou 59, are high-yield lines derived from the F1 hybrid rice, Nanyou 2 and Shanyou 2 by means of tissue culture and selec- tion. Five isozymes, esterase, peroxidase, ATP-ase, malate dehydrogenase and glulamate dehydrogenase from the new lines, the F1 hybrid rices and their parents, were analyzed by starch and polyacrylamid gel electrophoresis. There are no difference in zymogrames of ATPase, malate dehydrogenase, glulamate dehydrogenase, between the F1 hybrid and its parents. But the F1 hybrid rice contains complemental bands of anodal esterase EA2, EA3 and cathodal esterase EC1, EC2, EC3, EC4, The esterase zymogram of seeds of Nanhua 5, Nanhua 11 and Shanyou 39, Shanyou 59 could be observed in the progeny of the F2 hybrid rice. The results indicated that the new lines would be possibly derived from the progeny of the F1 hybrid by means of tissue culture and selection. 相似文献
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Crude extracts of 44 maize inbred seeds were treated under different temperatures, i. e. 50, 55, 60, 65 and 70℃, in order to determine their heat sensitivity of esterase isozymes. The results showed large discrepancy of heat sensitivity of anodic esterase isozymes between different or same relative mobility bands of isozyme, but similar inactivating temperature (65℃) of the cathodic ones for different inbreds. The heat sensitivity of isozymes for inbreds may be adopted in the identification of variation and purity of inbred and hybrid seeds of maize. 相似文献
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利用酯酶同工酶技术检测香菇双单杂交后代 总被引:8,自引:0,他引:8
选用香菇的野生株Q 与栽培株苏香的四种孢子单核体进行完全亲和双单杂交,运用拮抗试验并辅以液体出菇试验初步鉴定出12 个杂交后代,且对杂交后代酯酶同工酶进行了检测,并以聚类分析方法分析了菌株间酯酶同工酶酶谱的结果,较直观本质地反映了杂交后代及其与亲本之间的遗传差异,表明1 —12 号菌株是真正的双单杂交后代,认为菌株间酯酶同工酶酶相似系数值可以作为香菇遗传育种选择亲本的辅助的遗传标记 相似文献
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Structure of the Escherichia coli quorum sensing protein SdiA: activation of the folding switch by acyl homoserine lactones 总被引:1,自引:0,他引:1
Yao Y Martinez-Yamout MA Dickerson TJ Brogan AP Wright PE Dyson HJ 《Journal of molecular biology》2006,355(2):262-273
The three-dimensional structure of a complex between the N-terminal domain of the quorum sensing protein SdiA of Escherichia coli and a candidate autoinducer N-octanoyl-L-homoserine lactone (C8-HSL) has been calculated in solution from NMR data. The SdiA-HSL system shows the "folding switch" behavior that has been seen for quorum-sensing factors produced by other bacterial species. In the presence of C8-HSL, a significant proportion of the SdiA protein is produced in a folded, soluble form in an E.coli expression system, whereas in the absence of acyl homoserine lactones, the protein is expressed into insoluble inclusion bodies. In the three-dimensional structure, the autoinducer molecule is sequestered in a deep pocket in the hydrophobic core, forming an integral part of the core packing of the folded SdiA. The NMR spectra of the complex show that the bound C8-HSL is conformationally heterogeneous, either due to motion within the pocket or to heterogeneity of the bound structure. The C8-HSL conformation is defined by NOEs to the protein only at the terminal methyl group of the octanoyl chain. Unlike other well-studied bacterial quorum sensing systems such as LuxR of Vibrio fischeri and TraR of Agrobacterium tumefaciens, there is no endogenous autoinducer for SdiA in E.coli: the E.coli genome does not contain a gene analogous to the LuxI and TraI autoinducer synthetases. We show that two other homoserine lactone derivatives are also capable of acting as a folding-switch autoinducers for SdiA. The observed structural heterogeneity of the bound C8-HSL in the complex, together with the variety of autoinducer-type molecules that can apparently act as folding switches in this system, are consistent with the postulated biological function of the SdiA protein as a detector of the presence of other species of bacteria. 相似文献
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A new six-membered α,β-unsaturated lactone, lacquer allergic lactone, was isolated from the nonphenolic portion of chinese lacquer. Based on the result of clinical test on human bodies, it was an allergenically active volatile compound. The structure of this lactone was identified by means of IR, MS, NMR and chemical reaction. The urushiols was not the unique allergic principle since the actone was isolated. 相似文献
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真菌多糖抗肿瘤及免疫调节作用研究进展 总被引:14,自引:0,他引:14
真菌多糖被认为是目前最有开发前途的保健食品和药品的新资源之一,对真菌多糖的生物活性研究也是保健食品功能因子中最为炽热的研究热点。本文综述了近年来国内外真菌多糖抗肿瘤及免疫调节作用的研究进展。 相似文献