共查询到19条相似文献,搜索用时 156 毫秒
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酶法转化制备L-瓜氨酸 总被引:5,自引:2,他引:5
利用粪链球菌精氨酸脱亚胺酶转化L-精氨酸制备L-瓜氨酸。考察了菌龄、转化温度等多种因素对精氨酸脱亚胺酶活力的影响。酶法制备L-瓜氨酸的最适工艺条件是:菌体发酵时间20 h,转化温度37℃,转化液起始pH为6.0,ρ〔十六烷基三甲基溴化铵(CTAB)〕=0.3 g/L使酶活提高了414%。c(Co2+)=10-3mol/L使酶活增高约50%,c(Cu2+)=10-2mol/L或c(Zn2+)=10-2mol/L使酶活下降约50%。Ca2+、Mg2+和Mn2+对酶活影响较小。 相似文献
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以L-精氨酸为原料,经水杨醛催化消旋反应得到DL-精氨酸,在精氨酸酶的作用下,定向地将L-精氨酸转化为L-鸟氨酸和尿素,并经进一步分离纯化得到D-精氨酸和L-鸟氨酸盐酸盐。该文通过水杨醛对L-精氨酸进行消旋化,反应2.5 h,消旋率可达74.5%;同时,对L-精氨酸酶促反应条件进行了优化,结果表明,最佳反应条件为:37℃,pH=10,反应时间24 h,底物质量浓度40 g/L,酶质量浓度0.2 g/L,在该条件下转化率可达98.0%。经该法制备得到的产物D-精氨酸和L-鸟氨酸盐酸盐纯化后光学纯度可达99.0%。 相似文献
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József Huszár Dr. Éva Bozó Dr. Gyula Beke Krisztina Katalin Szalai Péter Kardos Dr. András Boros Dr. István Greiner Dr. János Éles 《ChemMedChem》2022,17(7):e202100707
Obesity is a global epidemic associated with multiple severe diseases. Several pharmacotherapies have been investigated including the antagonists of melanin concentrating hormone receptor 1 (MCHR1). The design, synthesis, and biological studies of novel MCHR1 antagonists based on benzofuro−pyridine and pyrazino−indole scaffold was performed. We confirmed that fine-tuning lipophilicity and basic pKa by modifying the benzyl group and introducing different substituents on the aliphatic nitrogen sidechain decreases both hERG inhibition and metabolic clearance. We have succeeded to develop excellent in vitro parameters in the case of compounds 17 (4-[(5-chloropyridin-2-yl)methoxy]-1-[4-(2-hydroxyethyl)-8-oxa-4-azatricyclo[7.4.0.02,7]trideca-1(13),2(7),9,11-tetraen-11-yl]-1,2-dihydropyridin-2-one monohydrochloride) and 23 g (4-[(5-chloropyridin-2-yl)methoxy]-1-(1,2,3,4-tetrahydropyrazino[1,2-a]indol-8-yl)pyridin-2(1H)-one monohydrochloride), which can be considered as valuable tools for further pharmacological investigation. 相似文献
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目的:研究高纯度绿原酸在不同条件下的稳定性。方法:采用高纯度绿原酸在抗氧化剂(亚硫酸氢钠、焦亚硫酸钠、L一半胱胺酸盐、维生素c)、不同pH值磷酸盐缓冲液、有机溶剂(甲醇、乙醇)、金属铜离子及络合剂及13一环糊精中的稳定性。结果:绿原酸在抗氧化剂L一半胱胺酸盐中最稳定,在酸性环境较碱性环境中更稳定,在上述有机溶剂中稳定,... 相似文献
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ABSTRACT The ion exchange kinetics of DL-lysine monohydrochloride on Amberlite IRA-420 have been studied. Ionic diffusivity of hydroxyl anion, which is supposed to be equal to the interdiffusion coefficient, has been evaluated by fitting experimental kinetic data to a theoretical model based on the continuity equation of the CI" anion in solution filling the pores of the resin. Because of changes of both viscosity with ionic concentration and co-ion behavior in solution at high concentrations, a variation of ionic diffusivity of hydroxyl anion has been observed. In order to predict the dynamic behavior of fixed beds a simple mathematical model including both equilibrium isotherm and ionic diffusivity of hydroxyl anion has been developed. Likewise, resin regeneration using NaOH solutions has been investigated. The results show the feasibility of the procedure of purification and regeneration and they have been used to design a plant for the treatment of 50 Tm/yr of DL-lysine monohydrochloride. 相似文献
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提出用高效液相色谱法测定1,3-二氨基胍盐酸盐的含量,选用甲醇与乙酸铵缓冲盐体积比75:25为流动相,c8色谱柱,检测波长314nm。试验结果表明:测试结果的相对标准偏差小于2.03%;回收率在97.8%~100.2%;1,3-二氨基胍盐酸盐和三氨基胍盐酸盐得到较好的分离。该法操作简单、实用且定量分析结果准确稳定。 相似文献
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L-Ornithine Monohydrochloride Doped Zinc Tris-Thiourea Sulphate Single Crystals for NLO Applications
Silicon - In the current study, transparent and bulk sized L-ornithine monohydrochloride (LOMHC) added zinc tris-thiourea sulphate (LOMHC-ZTS) single crystals are synthesized successfully by... 相似文献