水溶性羧甲基茯苓次聚糖的合成及性能研究

羧甲基茯苓次聚糖具有明显的抗肿瘤活性,有希望作为优良的细胞药物响应的免疫促进剂。本文研究了水溶性羧甲基茯苓次聚糖的合成工艺,确定了β-茯苓次聚糖羧甲基化条件.并用IR、~(13)C NMR对化合物进行了结构表征。     

甘氨酸的精制与研究

本文介绍一种新型甘氨酸的精制方法,利用此法制备的甘氨酸其收得率高,产品质量优于其它方法,完全符合中国药典标准。适用于药品的制备及食品、化工等方法。甘氨酸是一种具有重要工业价值的氨基酸,广泛用于农业,畜牧业、食品、医药及有机合成工业中,是重要的基本化工原料,同时也是合成其它氨基酸的原料,因而具有很高的工业价值。目前国内生产的甘氨酸由于纯度低,含杂质量高不符合医药品生产的使用要求,因此不能直接用于医药品的生产中,必须进行提纯精制。本人在查阅大量国内外有关资料的基础上,采用新型提纯工艺研制成功并于1989年10月通过技术鉴定,同年被授予国家专利权（专利号为89109134.3）。     

甘氨酸的精制与研究

本文介绍一种新型甘氨酸的精制方法,利用此法制备的甘氨酸其收得率高,产品质量优于其它方法,完全符合中国药典标准。适用于药品的制备及食品、化工等方法。甘氨酸是一种具有重要工业价值的氨基酸,广泛用于农业,畜牧业、食品、医药及有机合成工业中,是重要的基本化工原料,同时也是合成其它氨基酸的原料,因而具有很高的工业价值。目前国内生产的甘氨酸由于纯度低,含杂质量高不符合医药品生产的使用要求,因此不能直接用于医药品的生产中,必须进行提纯精制。本人在查阅大量国内外有关资料的基础上,采用新型提纯工艺研制成功并于1989年10月通过技术鉴定,同年被授予国家专利权(专利号为89109134.3)。     

半胱氨酸酯的几种合成方法

<正> 半胱氨酸脂(甲、乙脂)由于具有较强的抑菌效果,在医疗上被用于治疗呼吸系统疾病。在化妆品工业中大量用于配制高效冷烫精。本文介绍几种实验室合成半胱氨酸脂的方法。一、催化法在酸性介质中,半胱氨酸与甲醇发生如下反应:     

植物半胱氨酸合成及调控研究进展

硫是植物重要的营养元素。植物将氧化态硫吸收并还原后,首先合成半胱氨酸使其进入各种代谢途径。合成半胱氨酸的两种酶——丝氨酸乙酰转移酶和O-乙酰丝氨酸硫醇裂合酶均由多基因家族编码,并能可逆的结合形成二酶复合物进行有效的合成调节。本文对近年来半胱氨酸合成相关酶表达、定位、活性调控及转基因效果研究进展作了简要介绍,并对将来需要重点研究的方面作了展望。     

N－（膦羧甲基）α－甘氨酸的合成与应用

叙述了Ｎ－（膦羧甲基）α－甘氨酸的化学合成及其在除草剂方面的应用。该化合物有五条合成路线：曼尼斯反应、加成反应、取代反应、氧化还原反应和其他反应。其中曼尼斯反应较简便,可由甘氨酸、甲醛和亚磷酸酯一步合成标题化合物。Ｎ－（膦羧甲基）α－甘氨酸是一种高效广谱内吸传导型叶片喷药除草剂,它能有效地控制世界上危害最大的７８种恶性杂草中的７６种,还能“斩草除根”。除草机理为竞争性抑制５－烯醇丙酮莽草酸－３－磷酸合成酶（ＥＰＳＰａｓｅ）。     

半胱氨酸合成酶与β-氰基丙氨酸合成酶活性检测

植物半胱氨酸合成酶(Cysteine synthase,CSase)和β-氰基丙氨酸合成酶(β-cyanoalanine synthase,β-CAS)分别催化合成半胱氨酸(Cysteine,Cys)和β-氰基丙氨酸(β-Cyanoalanine,β-CA),它们在功能上冗余。本研究以山黧豆、苜蓿和玉米为主要材料,结合电泳对8种常见植物CSase和β-CAS粗酶活性进行了分析。结果表明,检测CSase活性时,8种植物两类粗酶的最适反应时间均为10min,最适pH均为8.0,底物O-乙酰-丝氨酸和Na2S最适浓度分别是10和5 mmol·L-1。检测β-CAS活性时,8种植物两类粗酶的最适反应时间均为30min,最适pH均在9~10范围内,底物Cys最适浓度均为3mmol·L-1,而底物KCN最适浓度前者为80mmol·L-1,后者为3mmol·L-1。8种植物中,CSase活性在种、种内组织间差别不是很大,但β-CAS活性则相反,尤其在茎叶和根中差别较大。     

双戊烯合成萜马加成物反应的研究

本文以稀土金属氧化物(盐)为催化剂,催化工业双戊烯与顺丁烯二酸酐连续进行异构/Diels-Alder反应,合成出萜烯/马来酸酐加成物;用气相色谱法跟踪研究了反应的进程,并模拟了反应的动力学方程,初步鉴定了主产物的结构。结果表明本合成反应条件温和,反应易于控制,催化剂易于回收,产物得率比文献值高近20个百分点,产物纯度大于90％,且产物性能能满足进一步合成的要求。     

ENZYMES CATALYZING THE DE NOVO SYNTHESIS OF METHYL GROUPS IN THE BRAIN AND OTHER TISSUES OF THE RAT

—Rat brain contains all three of the enzymes required for de novo synthesis of the methyl group of methionine (serine transhydroxymethylase, methylene reductase, and [B₁₂]transmethylase) in activities comparable to those found in liver and kidney. The activities of methylene reductase in female kidney, and of [B12]transmethylase in female brain and kidney, are higher than in the corresponding male tissues. Liver and kidney extracts contain an inhibitor of methylene reductase not present in brain extracts. This inhibitor differs from S-adenosylmethionine (SAM), which also inhibits methylene reductase in both liver and brain homogenates. The administration of l -DOPA to rats, which has been previously shown to deplete brain S-adenosylmethionine, also reduces the activity of brain [B₁₂]transmethylase if assayed without added SAM. Since SAM is required for activity of this enzyme, its decreased activity probably results from the decline in brain SAM concentration. De now synthesis of methyl groups could be a mechanism by which the brain maintains its level of methionine in the face of increased methyl group utilization after administration of l -DOPA.     

A COMPARATIVE STUDY ON THE SYNTHESIS OF THE NATRIURETIC HORMONE DOPAMINE IN OK AND LLC-PK1CELLS

TheV_maxvalues (in nmol/mg protein/15 min) for AAAD in OK cells (0.94±0.08) were found to be significantly (P<0.01) lower than those observed in LLC-PK₁cells (4.37±0.08). However, in both cell lines decarboxylation reaction was a saturable process with similarK_mvalues (OK cells=1.1 mm (0.3, 1.8); LLC-PK₁cells=1.8 mm (1.6, 2.1)). Contrariwise to OK cells, decarboxylation ofl -DOPA to dopamine in LLC-PK₁cells followed a linear (7.6±0.1 pmol/mg protein/min) non-saturable kinetics till 120 min of incubation. The formation of dopamine from increasing concentrations ofl -DOPA (10 to 500 μm ) followed a non-linear kinetics in both cell lines; the process ofl -DOPA decarboxylation was saturated at low concentrations ofl -DOPA with an apparentK_mvalue of 11 μm (0.2, 22.6) in OK cells and 27.4 μm (11.1, 43.7) in LLC-PK₁cells. The formation of dopamine in LLC-PK₁cells (V_max=2097±113 pmol/mg protein/6 min) was 13.7-fold that occurred in OK cells (V_max=153±10 pmol/mg protein/6 min). In conclusion, LLC-PK₁cells appear to be endowed with a greater ability to form dopamine from exogenousl -DOPA when compared to OK cells.     

SYNTHESIS AND STUDY OF THE FLUORESCEIN CONJUGATE OF THE NUCLEOTIDE dPTP

The synthesis of a fluorescein conjugate on the non-natural base P is described. The ability of the newly synthesised fluorescein - dPTP and of a fluorescein-11-dUTP to compete with the natural nucleotide TTP was also studied. Overall the efficiency of labelling a nucleic acid with a fluorescein moiety was found to be approximately equal.     

STUDIES ON THE RELATIONSHIP BETWEEN GABA SYNTHESIS AND PROTEIN SYNTHESIS IN BRAIN

Abstract— The synthesis of γ-aminobutyric acid (GABA) in mouse brain was decreased by treatment of the animals with pyridoxal phosphate- γ-glutamylhydrazone, an inhibitor of glutamate decarboxylase in vivo. Under these experimental conditions the following parameters were studied: (1) the incorporation of labeled leucine in vivo , into protein of brain subcellular fractions; (2) the brain polysome profile; (3) the incorporation of labeled leucine into protein in vitro , in ribosomal preparations isolated from brain tissue. In other experiments, GABA synthesis was also decreased in brain cortex slices by preincubation with aminooxyacetic acid. The incorporation of [³H]leucine or [¹⁴C]leucine into protein in these slices was studied, and samples from the proteins were subjected to acrylamide-sodium dodecylsulfate gel electrophoresis. Radioactivity was counted in slices of the gel. The results of the experiments in vivo and in vitro indicate that the previously reported decrease of protein synthesis induced by an inhibition of GABA synthesis affects proteins of all subcellular fractions and all populations of protein as separated by gel electrophoresis. The polysome profile from brains of mice with decreased GABA synthesis was similar to that of control mice. This result differs from that found when brain protein synthesis is inhibited by dopamine and serotonin.     

山苍子油的精制、分析及成份研究

本文报告一种山苍子油的精制、分析方法和成分研究.作者采用间歇精馏法从山苍子油中单离柠檬醛,可使柠檬醛含量达到90％以上;并使用毛细管气相色谱法定量测定了山苍子油中柠檬醛含量;还通过GC/ITD/COM系统从山苍子油中成功地分离出50种左右的成分,其中30多种化合物己被鉴定.     

水溶性羟丙基甲壳素的合成及性能研究

本文研究了水溶性羟丙基甲壳素的合成工艺,确定了甲壳素羟丙基化的条件,并用ＩＲ、ＮＭＲ对化合物进行了结构表征。