有机溶剂/缓冲液两相体系中全细胞催化拆分环氧氯丙烷

研究了有机溶剂/缓冲液两相体系中重组大肠杆菌E.coli BL21 (DE3)全细胞水解动力学拆分外消旋环氧氯丙烷制备(R)-环氧氯丙烷的过程.结果表明,最适反应条件为:最适有机溶剂异辛烷与缓冲液的体积比7:3,最适缓冲液pH 8.0,底物浓度574mmol/L,全细胞加入量0.07g湿菌体/ml溶液,温度30℃.在此条件下于1L反应器中反应45min,(R)-环氧氯丙烷的摩尔产率、光学纯度和时空产率分别达到37.5%,99.3%ee和0.286mol/(L·h).与单一水相体系相比,异辛烷/缓冲液两相体系中底物浓度和(R)-环氧氯丙烷时空产率分别提高了55.2%和98.6%.     

单壁碳纳米管对C-C键水解酶BphD的固定化性能

采用修饰与未修饰单壁碳纳米管固定C-C键水解酶BphD,并对固定化酶的相对活性、稳定性、重复使用性进行了考察.结果表明,未修饰单壁碳纳米管固定的BphD相对活性为游离态的52.5%,其热稳定性和在变性剂中的稳定性均有所提高,且重复使用10次仍可保持初始活力的90%.修饰单壁碳纳米管固定的BphD相对活性可达99.7%,但其稳定性没有明显提高.同源模建及分子对接分析结果显示,未修饰的单壁碳纳米管对BphD亚基之间的联系可能存在干扰作用,从而对其活性产生影响.     

Fatty acid amide hydrolase inhibitors. 2. Novel synthesis of sterically hindered azabenzhydryl ethers and an improved synthesis of VER-156084

We report an improved synthesis of the fatty acid amide hydrolase (FAAH) inhibitor VER-156084. The key step is a novel, environmentally benign etherification to form an unusual, highly hindered azabenzhydryl ether. The method is applied to a variety of primary and secondary alcohols.     

A New Triterpenoid Glycoside from Decaisnea Fargesii

Deculsnea./al..gesiiFranch.IsatraditionalChinesemedicinalplantwidely'distributedinChina.usedasananti-rheumaticandalltitussivedrugforalongtimeinChinesefolkmedicine'.Itsmethanolextractshowedantitunlouracidityif71)if)oagainstS:sl},HepaandEhrlichcellsanditsphytochemicalstudiesonsaponinshasreported'.Asacontinuationofthestudiesonthisplant,wepresentthespectralandchemicalevidenceofthestructureofanewdecaisosideF.Thedriedstems(2.23kg)werepercolated\vith95%EtOH.Afterremovalofthepercolatesb}evaporat…     

Synthesis of Long Chain Fatty Acids Acylated Coumarin Glycoside Esters with Lipase as Catalyst

A series of novel coumarin glycoside esters(1―9) was synthesized through the acylation reaction of 4-methylcoumarin-7-O-β-D-glucoside(11) with different long chain fatty acids catalyzed by lipase in organic medium. The acylation occurred regioselectively at the 6'-OH of glycosyl moiety. The enzymatic synthesis was optimized to achieve 54%―70% yield using immobilized lipase(Novozym 435, 10 mg/mL) as catalyst and acetone and pyridine(9:1, volume ratio, water content<1%) as solvent with an acyl donor/coumarin glycoside molar ratio of 10:1 at a temperature of 40―50 ℃ for 96 h. All the synthesized compounds were confirmed.     

介孔材料固定化酶*

本文综述了近年来酶在介孔材料上的固定化研究新进展,重点介绍了水解酶类的脂肪酶、蛋白酶、青霉素G酰化酶等和氧化还原酶类的辣根过氧化物酶、氯过氧化物酶、漆酶等在介孔材料上的固定化研究现状,并对介孔材料固定化酶的发展前景进行了展望。     

酚类糖苷缀合物的合成、表征及美白活性

根据拼合原理,以对苯二酚(p-HQ)、间苯二酚(m-HQ)及邻苯二酚(o-HQ)为先导化合物,通过一侧酚羟基的苄基保护、引入溴乙酸甲酯、还原、与3种糖元偶联、脱除保护基得到9种目标化合物。 同样以3-(4-羟基苯基)-1-丙醇为起始物质,通过苄基保护、与3种糖元偶联、脱除保护基得到3种目标化合物。 通过IR、¹H NMR、¹³C NMR、HRMS等波谱分析方法对所合成的12种目标化合物进行了结构表征。 对合成的酚类糖苷缀合物进行了美白活性研究。 结果表明,化合物p-HQ-6a、m-HQ-7a、p-HQ-6b、m-HQ-6b、o-HQ-6b、p-HQ-6c、m-HQ-7c、L-3a和L-4b对酪氨酸酶有抑制作用,其中o-HQ-6b和p-HQ-6c对酪氨酸酶的抑制作用优于阳性对照物α-熊果苷。     

A Novel Thermostable β-Galactosidase from Geobaciilus kaustophilus HTA42

A novel thermostable β-galactosidase gene, designated as GkGallA, from the thermophilic bacterium Geobacillus kaustophilus HTA426 was cloned and heterologously overexpressed in Escherichia coli（E, coli）. Based on the sequence analysis, GkGallA belongs to the glycosyl hydrolase family 1 that was the first β-galactosidase of bacterial origins expressed by us in this family. The apparent molecular weight of GkGallA determined by sodium deodecyl sulfate-polyacrylamide gel electrophoresis is 52000. It exhibited the highest activity toward p-nitrophenyl-β-D-galactopyranoside at pH 7.8 and 70℃ and displayed high thermal stability, Divalent cations are prerequisite for the activity of GKGallA, with the highest activity in the presence of Mn2＋. Moreover, the three-dimensional structure of GkGaI1A was modeled to speculate the structure of the catalytic residues and the reac- tion mechanism. The catalytic residues consisting of Glu166 and Glu355 were verified by site-directed mutagenesis.