固定化嗜热菌蛋白酶催化合成二肽甜味剂Aspartame

以氨丙基多孔硅球作载体,以戊二醛作交联剂制备的固定化嗜热菌蛋白酶催化合成Aspartame前体,通过酸化脱盐、氢化等反应得到二肽甜味剂Aspartame。研究了反应条件对合成Aspartame前体产率的影响,考察了固定化酶的重复使用性能。结果表明,固定化酶在水相中能较好的催化合成Aspartame前体,且具有良好的重复使用性能。     

DL-苯丙氨酸-1-14C化学合成及酶促拆分

本文报道 DL-苯丙氨酸-1-(14)~C 的合成,并利用嗜热菌蛋白酶酶促拆分光学异构体。化学产率和放化产率一致,可达67%,标记化合物的放化纯度高于95%。     

聚丙烯偕胺肟-聚乙烯醇大孔球状载体的合成及固定化嗜热菌蛋白酶的研究

以线型聚醋酸乙烯酯为致孔剂,由悬浮聚合制得了丙烯腈-醋酸乙烯酯-二乙烯基苯大孔树脂(MR-AV树脂),通过MR-AV树脂的化学改性,合成了聚丙烯偕胺肟-聚乙烯醇大孔球状载体(MR-AVa载体),用FT-IR、SEM、压汞仪和元素分析法研究了树脂及载体的结构与组成,结果表明MR-AVa载体含氮量较高,具有一定的亲水性,且平均孔径大于8,000(?),嗜热菌蛋白酶用戊二醛固定于所得载体之上。以酪蛋白为底物,考察了固定化嗜热菌蛋白酶的催化水解活性及其影响因素,与可溶酶比较,固定化嗜热菌蛋白酶的热稳定性和抗抑制能力显著提高,当载体孔径较大时,所得固定化酶显示出较好的催化活性。     

Papain Catalyzed Synthesis of Aspartyl Dipeptides

Procedures have been developed for the preparation of aspartyl containing dipeptides P-L-Asp-AA₂ (P=Boc, Cbz and Moz; AA₂=Phe-R or Ala-R; R=OH, OBzl and OTMB) using papain as a catalyst. The pH dependent of esterase activity by papain catalyzed hydrolysis have been studied. The papain catalyzing reaction can be reacted in aqueous solution, buffer solution or cosolvent system in a thermodynamically controlled approach. A procedure for the conversion of the artificial sweetner precursor P-Asp-Phe-OH to the aspartame is studied also.     

Enzymatic Synthesis of Agmatine by Immobilized Escherichia coli Cells with Arginine Decarboxylase Activity

A new method for the enzymatic synthesis of agmatine by immobilized Escherichia coli cells with arginine decarboxylase(ADC) activity was established and a series of optimal reaction conditions was set down. The arginine decarboxylase showed the maximum activity when the pyridoxal phosphate(PLP) concentration was 50 mmol/L, pH=7 and 45 °C. The arginine decarboxylase exhibited the maximum production efficiency when the substrate concentration was 100 mmol/L and the reaction time was 15 h. It was also observed that the appropriate concentration of Mg2+, especially at 0.5 mmol/L promoted the arginine decarboxylase activity; Mn2+ had little effect on the arginine decarboxylase activity. The inhibition of Cu2+ and Zn2+ to the arginine decarboxylase activity was significant. The immobilized cells were continuously used 6 times and the average conversion rate during the six-time usage was 55.6%. The immobilized cells exhibited favourable operational stability. After optimization, the maximally cumulative amount of agmatine could be up to 20 g/L. In addition, this method can also catalyze D,L-arginine to agmatine, leaving the pure optically D-arginine simultaneously. The method has a very important guiding significance to the enzymatic preparation of agmatine.     

固载化酶催化合成多肽的研究进展

评述了溶剂、载体性质与固载化方法、pH值、底物浓度以及反应温度等因素对固载化酶催化合成肽反应的影响,并概括了固载化酶催化合成生物活性肽、寡肽等方面的研究与应用.     

泰妥拉唑的合成与拆分

2-巯基-5-甲氧基咪唑并[4,5]-吡啶和2-氯甲基-4-甲氧基-3,5-二甲基-吡啶盐酸盐在碱性条件下经亲核取代反应制得2-[2-(3,5-二甲基)-4-甲氧基甲基硫醚-5-甲氧基]咪唑并[4,5]-吡啶(3);3经间氯过氧苯甲酸氧化后用盐酸酸化合成了消旋泰妥拉唑[(±)-5];分别以(S)-酒石酸二乙酯和(S)-联萘酚为拆分剂,(±)-5经包结拆分制得(S)-5,其结构经1H NMR和IR确证。     

反相离子对液相色谱法分析天冬二肽

提出了一种反相离子对液相色谱法分析天冬二肽的分析技术；采用C18为分析柱，以三氟乙酸为离子对试剂，乙腈-磷酸二氢钾水溶液为流动相；方法不仅适用于天冬二肽产品的纯度分析，而且适用于天冬二肽合成过程中的中间体及副产物的分析；方法具有分析速度快、准确度高、操作简单、实用性强等优点。     

阿斯巴甜的合成及应用

阿斯巴甜是一种新型甜味剂。介绍了阿斯巴甜的特点、发展及广阔的应用前景,评述了国内外的合成方法。     

酶促水解法拆分布洛芬乙酯的工艺研究

以布洛芬乙酯为反应底物,探索了酶促水解法拆分布洛芬的工艺。以曲拉通X-100为表面活性剂,利用南极假丝酵母脂肪酶B（CAL-B）催化拆分外消旋布洛芬乙酯,并对表面活性剂含量、有机溶剂种类和添加量、酶量、缓冲溶液pH、温度及时间等反应条件进行了优化;得到的最佳反应条件为：在pH为9.0的缓冲溶液中,添加80 mg曲拉通X-100、50 μL二氯甲烷和15 mg CAL-B,于30℃下反应48 h;在该条件下,S-布洛芬乙酯的剩余率（C）为65%,布洛芬乙酯的对映体过量值（ees）为94%。     

2-甲基-3-双取代基-4,5-二氢异噁唑衍生物的合成及其拆分

3-(1′,2′-二-O-环己叉二氧乙基)异噁唑啉盐(2)与MeMgBr(或在二异丙基胺和正丁基锂存在下与乙酸乙酯)进行亲核加成反应合成了2,3-二甲基-3-(1′,2′-二-O-环己叉二氧乙基)-4,5-二氢异噁唑(3)[或2-甲基-3-(乙氧羰甲基)-3-(1′,2′-二-O-环己叉二氧乙基)-4,5-二氢异噁唑(4)]。3和4经MPLC拆分得到了非对映体3a,3b,4a和4b,其结构经1HNMR,13C-NMR,IR和元素分析表征。