槲皮素对甲硫氨酸负载大鼠氨基酸代谢的影响

为探讨槲皮素对甲硫氨酸(Met)负载大鼠氨基酸代谢的影响,将Wistar大鼠24只随机分为3组,即对照组、1％甲硫氨酸组以及1％甲硫氨酸和0.5％槲皮素组,喂养6周后,采用高压液相色谱法测定血清中半胱氨酸含量,全自动氨基酸分析仪测定血清中其他氨基酸含量.结果显示,1％甲硫氨酸干预后除对牛磺酸产生显著影响外,对其他氨基酸没有明显影响.0.5％槲皮素干预后,血清必需氨基酸苏氨酸、缬氨酸含量较1％ Met组显著升高(p＜0.05),牛磺酸、缬氨酸、亮氨酸和异亮氨酸较对照组亦显著升高(p＜0.05),而血清丝氨酸和脯氨酸含量较对照组显著降低(p＜0.05).结果表明,槲皮素可能加强甲硫氨酸转硫化代谢途径.     

应用离子交换膜进行蛋白质水解液脱酸和酸的回收

<正> 以废蚕丝、鱼皮、明胶、血粉等原料制备丝氨酸、脯氨酸、精氨酸等时,先用盐酸把原料水解成合有各种氨基酸的水解液。为了用离子交换树脂柱层析分离得到所需的氨基酸,首先要把水解液反复减压蒸馏浓缩,以除去水解液中的大部分酸,或者用专用脱酸离子交换树脂柱脱酸。前者消耗大量的能源,后者要用酸碱再生树脂。如能把水解液中的盐酸用一种简单的方法回收,免去除酸工序或减少除酸工序的工作量,回收的酸加以利用,既可降低生产成本,又可减少三废。上海硅钢片厂应     

淮山药中氨基酸含量的测定

用氨基酸分析仪测定了淮山药中各种氨基酸的组成。淮山药样品经酸水解处理,用氨基酸分析仪进行分析,结果表明：淮山药中含有苏氨酸,缬氨酸,蛋氨酸,苯丙氨酸,异亮氨酸,亮氨酸和赖氨酸等17种氨基酸,总氨基酸质量分数为7．256％,其中人体必需氨基酸的含量占总氨基酸含量的25．32％;说明淮山药在医学和营养学上都有很高的研究价值。     

淮山药中氨基酸含量的测定

用氨基酸分析仪测定了淮山药中各种氨基酸的组成。淮山药样品经酸水解处理,用氨基酸分析仪进行分析,结果表明:淮山药中含有苏氨酸,缬氨酸,蛋氨酸,苯丙氨酸,异亮氨酸,亮氨酸和赖氨酸等17种氨基酸,总氨基酸质量分数为7.256％,其中人体必需氨基酸的含量占总氨基酸含量的25.32％;说明淮山药在医学和营养学上都有很高的研究价值。     

蚕蛹蛋白质的酶—酸两步水解

将木瓜蛋白酶催化水解和酸水解联合起来应用于水解蚕蛹蛋白质制备氨基酸。与单纯酶解(水解时间48h)或酸水解(水解时间24h)相比,水解时间分别缩短了2/3和1/3,后处理简化,能耗降低。研究了蚕蛹蛋白质水解的影响因素,在适宜条件下,得到有香味的混合氨基酸,收率为98.5％(对蛋白质),其中含有17种游离氨基酸(色氨酸未测),含量为47.9％。     

HPLC法分析乳清蛋白对糖尿病模型小鼠血浆氨基酸组分的影响

为寻求有效的氨基酸分离方法并探讨乳清蛋白对2型糖尿病防治的作用机制,采用HPLC法分析乳清蛋白中氨基酸组分及含量;分别以0％、10％、20％和40％的乳清蛋白(WP)灌胃1型、2型糖尿病模型组、正常组小鼠,4周后观察各组血浆氨基酸的变化.乳清蛋白中亮氨酸、异亮氨酸、缬氨酸分别占氨基酸总量的14.40％、5.93％和5....     

用732阳离子交换树脂柱提取碱性氨基酸工艺研究

本文是从棉籽饼粕中,应用７３２阳离子树脂柱提取碱性氨基酸。研究结果表明,碱性氨基酸与中性氨基酸之间交叉部分较小。因此,本法即简化了提取工序,又缩短了操作时间,大大提高了氨基酸的分离效果。     

蚯蚓活动对土壤氨基酸组分及含量的影响

通过室内培养试验,研究了赤子爱胜蚓(Eisenia foetida)和威廉环毛蚓(Metaphire guillelmi)对土壤氨基酸组分及含量的影响,并探讨了两种不同生活型蚯蚓作用效果的异同。结果表明:蚯蚓活动可显著改变土壤氨基酸含量,爱胜蚓作用下土壤酸解氨基酸和游离氨基酸分别增加5.08 g/kg和7.72 mg/kg,环毛蚓作用下土壤酸解氨基酸和游离氨基酸分别增加3.86 g/kg和4.44mg/kg。各处理酸解氨基酸均以中性氨基酸所占比例为最大(平均51.9%),酸性氨基酸次之(平均23.3%),而含硫氨基酸(平均14.4%)及碱性氨基酸最少(平均10.4%)。各处理游离氨基酸同样以中性氨基酸为主,平均54.4%,而以碱性氨基酸含量最少,平均仅为7.2%。蚯蚓活动并未改变土壤氨基酸可检出种类,各处理分别检测出16种酸解氨基酸和14种游离氨基酸。土壤酸解氨基酸和游离氨基酸组分含量在蚯蚓作用下均有明显改变:加入爱胜蚓后土壤酸解氨基酸组分中天冬氨酸、精氨酸、甲硫氨酸、丙氨酸、赖氨酸和甘氨酸增幅较高,均在85.7%以上,缬氨酸、苏氨酸、丝氨酸、谷氨酸、亮氨酸、酪氨酸和组氨酸增幅较小在40.7%—62.7%间波动;加入环毛蚓后土壤酸解氨基酸组分中甲硫氨酸、赖氨酸、天冬氨酸、酪氨酸和丙氨酸增幅较大,均在71.9%以上,甘氨酸、精氨酸、异亮氨酸增幅适中,分别为56.8%、55.6%和54.9%;丝氨酸、亮氨酸、苏氨酸、谷氨酸、组氨酸和苯丙氨酸增幅最小,均在40%以下;游离氨基酸组分中组氨酸、精氨酸、甘氨酸、亮氨酸、异亮氨酸和丙氨酸在加入爱胜蚓后增加的幅度较大,增幅在150.0%以上,增幅较为缓和的氨基酸组分有天冬氨酸、苏氨酸、丝氨酸、缬氨酸、谷氨酸和苯丙氨酸,介于58.8%—92.1%之间;环毛蚓作用下,天冬氨酸、精氨酸、丝氨酸和异亮氨酸增幅最大,分别为184.2%、173.3%、163.0%和116.6%;苏氨酸、亮氨酸、缬氨酸和甘氨酸增幅较缓,介于52.3%—92.7%之间;谷氨酸、组氨酸、苯丙氨酸、丙氨酸和甲硫氨酸增幅较低,均在33.1%之下;而半胱氨酸在蚯蚓作用下显著降低,降幅为11.8%。对比两种生活型蚯蚓作用效果可知,土壤氨基酸总含量及各组分含量在爱胜蚓和环毛蚓作用下的增加或减少趋势相同(土壤酸解氨基酸组分缬氨酸除外),但改变幅度却存在明显差异,总体而言,爱胜蚓作用效果优于环毛蚓。     

猪血蛋白的酶水解及氨基酸含量

以AS1.398中性蛋白酶、胰蛋白酶、木瓜蛋白酶和菠萝蛋白酶对猪血蛋白进行水解,AS1.398中性蛋白酶对猪血蛋白的水解能力最强。采用活性炭对酶水解液进行脱色。脱色后的酶水解液中含有18种氨基酸,必需氨基酸占总氨基酸的39.18%。     

氨基酸制备色谱——丙氨酸、缬氨酸和亮氨酸制备柱柱效率研究

现代液相色谱已从分析色谱发展到制备色谱,为了研究氨基酸制备色谱柱柱效率,我们从液相色谱理论的十几个基本关系式中归纳出五个基本方程式,用以评价丙氨酸、缬氨酸和亮氨酸制备柱柱效率。初步试验结果表明,对强酸性阳离子交换树脂柱而言: 1.凝胶型离子交换树脂柱柱效率高于普通大孔型离子交换树脂柱柱效率,而与本室合成的Dpsc大孔型离子交换树脂柱柱效率相当。 2.凝胶型离子交换树脂中,低交联度离子交换树脂有利于提高缬氨酸和亮氨酸制备柱柱效率,可较好地分离缬氨酸和亮氨酸;较高交联度离子交换树脂有利于提高丙氨酸和缬氨酸制备柱柱效率,可较好地分离丙氨酸和缬氨酸。将不同的离子交换树柱组合起来,可以提高丙氨酸,缬氨酸和亮氨酸的分离度,提高氨基酸的回收率。这项研究成果已应用到从猪血粉、猪毛等天然蛋白质酸水解物中系统分离多种氨基酸,以及分别从缬氨酸、亮氨酸(异亮氨酸)发醇液中分离纯化缬氨酸、亮氨酸(异亮氨酸)。     

A versatile synthetic route to chiral quinoxaline derivatives from amino acids precursors

The synthesis of N-protected L-amino acid (3-benzylquinoxalin-2-yl) hydrazide derivatives is reported here. 3-Benzyl-2-hydrazinoquinoxaline was prepared and then coupled with N-Boc-L-amino acids including; Alanine, Valine, Leucine, Phenylalanine, Tyrosine, Serine and Proline in the presence of HBTU as a coupling reagent to provide the expected product with high yield and purity. The products were deprotected by p-toluenesulphonic acid in acetonitrile and then the tosylate salts were evaluated for antibacterial and antifungal activity.     

Amino acid profiling of <Emphasis Type="Italic">Sorghum bicolor</Emphasis> vis-à-vis <Emphasis Type="Italic">Chilo partellus</Emphasis> (Swinhoe) for biochemical interactions and plant resistance

Amount of certain amino acids required by herbivores, and their availability in host plants are of crucial importance for insect growth, development, and life processes. Therefore, we carried out profiling and quantification of 17 amino acids in diverse sorghum genotypes, and on the Chilo partellus larvae reared on them, to understand the association and contribution of different amino acids in plant resistance to insects. Sorghum germplasm lines IS 2205 and IS 2123 had severe detrimental effects on the development and survival of C. partellus followed by varieties ICSV 700 and ICSV 708 in comparison to susceptible check, Swarna. Profiling of sorghum seedlings, seeds, and the C. partellus larvae fed on these genotypes for 17 amino acids revealed that Arginine, Glycine, Isoleucine, Leucine, Proline, and Valine in sorghum seedlings and the C. partellus larvae had significant and positive association, suggesting their role in the development and survival, while negative association of Cystine indicated its contribution in plant defense. Furthermore, C. partellus acquired less of cyclic and aliphatic amino acids per unit amount from the test resistant genotypes, while more from the susceptible check, than their presence in the seedlings. Present studies suggest that Alanine, Cystine, Glycine, and Proline contents in C. partellus larvae; Cystine and Proline contents in sorghum seedlings; and Methionine content in sorghum seeds, have significant and negative association, and contribute to explain?>93% and >96%, respectively, of the variability in antibiosis mechanism and overall resistance to C. partellus. These studies have implications for antibiosis and nutritional mechanism of host plant–insect interactions in sorghum against C. partellus.     

A versatile synthetic route to chiral quinoxaline derivatives from amino acids precursors

Summary The synthesis ofN-protected L-amino acid (3-benzylquinoxalin-2-yl) hydrazide derivatives is reported here. 3-Benzyl-2-hydrazinoquinoxaline was prepared and then coupled withN-Boc-L-amino acids including; Alanine, Valine, Leucine, Phenylalanine, Tyrosine, Serine and Proline in the presence of HBTU as a coupling reagent to provide the expected product with high yield and purity. The products were deprotected by p-toluenesulphonic acid in acetonitrile and then the tosylate salts were evaluated for antibacterial and antifungal activity. Abbreviations: HBTU, N-[(1H-benzotriazol-1-yl)(dimethylamino)methylene]-N-methylmethanaminium hexafluorophosphate N-oxide Boc,t-butyloxycarbonyl, DIEA, diisopropylethylamine; DMF, N,N-dimethylformamide; PTSA, p-toluenesulphonic acid, TEA, triethyl amine. Amino acids are abbreviated and designated following the rules of the IUPAC-IUB Commission of BiochemicalNomenclature (J. Biol. Chem., 247 (1972) 977).     

三线闭壳龟肌肉氨基酸分析

应用美国ＢＥＣＫＭＡＮ １２１ ＭＢ型全自动氨基酸分析仪对三线闭壳龟肌肉中的氨基酸种类及含量进行了分析。三线闭壳龟肌肉中能检出的氨基酸有１７种,每种氨基酸的含量如下：天门冬氨酸６９０５ｍｇ／１００ｇ,苏氨酸３２４０ｍｇ／１００ｇ,丝氨酸２９２９ｍｇ／１００ｇ,谷氨酸１２７４０ｍｇ／１００ｇ,脯酸２６８５ｇｍ／１００ｇ,甘氨酸２９５３ｍｇ／１００ｇ,丙氨酸３４８３ｍｇ／１００ｇ,酪氨酸２９１０ｍｇ／     

Studies on the cholesterol synthesis in the human adipose tissue. II. Mechanism of metabolic shifts and regulation of cholesterol through ascorbic acid.

Ratios of yields of cholesterol in different media with different metabolites (200 estimations) show that if the initial normal quantity in a system is X, glucose makes it 4X which is then reduced by the amino acids and ascorbic acid. Alanine, Serine, Threonine, Cysteine, Cystine and Lysine reduce it to 2X. Glycine, Valine, Leucine, Aspartic, Phenylalanine, Tyrosine, Tryptophan roughly increase it to 6X. Other amino acids are intermediate between the above sets. Balanced amino acids and fatty acids keep up the glucose value 4X but the individual amino acids behave as above. Ascorbic acid reduces the quantity of cholesterol everywhere from one third to one half bringing it back to normal X. Since it is not directly involved in the cholesterol synthesis, it must be acting through the pyridine nucleotides. The interesting feature is that the C/H ratio in the amino acids corresponds to the yield of cholesterol with respect to glucose saline yield = 1. Mechanism of metabolic shifts has been discussed on the empirical basis as also on the basis of the change in ratios of NAD+ (NADP+) to NADH2 (NADPH2) through ascorbic acid.     

抗植物病毒农药“病毒煞”的氨基酸成分分析

本文通过对抗植物病毒农药“病毒煞”的氨基酸成分进行分析,共含有１８种氨基酸,其中脯氨酸、谷氨酸、精氨酸和天冬氨酸含量较高,约占水解氨基酸总量的４７％;含有１９种游离氨基酸,脯氨酸含量最高,占游离氨基酸总量的５１％,说明氨基酸可能是其防病增产的有效成分之一。     

The involvement of amino acids in latex lipid synthesis in Euphorbia lathyris seedlings

The breakdown of triglycerides and proteins in the endosperm of Euphorbia lathyris was assayed in a 14 day germination period. Six days after germination, the average daily production was 2.7 μmol of amino acids. Arginine, glutamine, asparagine and glutamic acid accounted for 53% of the total amino acids. Excised cotyledons with 1 cm hypocotyls were used for amino acid uptake and their involvement in terpenoid synthesis was studied. Glutamine and aspartate were hardly involved in apolar lipid synthesis. Leucine, isoleucine, valine and threonine were mainly incorporated into the triterpenes in the laticifers. Alanine and serine were also involved in phytosterol synthesis in the adjacent tissue. In the 14 day germination period, ca3% of the daily yield of latex triterpenes may be synthesized from a variety of amino acids.     

Free amino acids in some sponges

Most invertebrates, particularly those of marine origin, have relatively high concentrations of free amino acids which are considered an important constituent of their osmoregulatory mechanisms [1]. Very little information is available on the free amino acid distribution in Porifera [2,3]. Common amino acids in some sponges were recognised by paper chromatography by Inskip and Cassidy [4] and Ackermann et al. [5,6] included a few sponges in their survey of the occurence of nitrogen compounds in marine invertebrates. More recently Bergquist and Hartman [7] surveyed semiquantitatively the distribution of free amino acids in several sponges. In the present paper we report on the amino acid composition of 12 species of sponges belonging to the class Demospongiae as a part of a study on the metabolites of Porifera [8]. Fresh sponges were extracted with aqueous ethanol. The organic solvent was removed and the aqueous solution, after removal of the ether soluble compounds, was separated into cationic, anionic and neutral fractions by ion-exchange chromatography. The cation fraction was analysed for amino acids using an automatic amino acid analyser. The results, which are presented in Table 1, show that all species of sponges examined have a similar composition in common amino acids. Glycine almost always appears as the dominant protein amino acid, followed by high concentrations of alanine and glutamic acid, whereas relatively lower concentrations of basic amino acids are present. In Axinella cannabina, Chondrosia reniformis, Chondrilla nucula, Cliona viridis and Hymeniacidon sanguinea, glycine represents more than 77% of the total amino acids. The high percentage of free glycine (90.4%) in Chondrosia reniformis is noteworthy. The anionic and the neutral fractions were examined for sulfur-containing amino acids using PC. Taurine (Table 2) was detected in all the Porifera examined; this is in agreement with previous observations [5–7]. N-Methyltaurine was identified in some of the species examined, whereas neither N,N-dimethyltaurine nor N,N,N-trimethyltaurine were found.     

兴安落叶松游离氨基酸的动态变化与损伤因子的关系

为研究不同损伤因子及其不同损伤程度对落叶松游离氨基酸组分及其含量的影响,用剪叶和落叶松毛虫(Dendrolimussuperans)取食损伤兴安落叶松(Larixgmelinii)幼苗,使用HPLC柱前AccQ.Tag衍生法测定针叶内游离氨基酸的组成及含量的变化。结果表明,松针中含有17种游离氨基酸,以苯丙氨酸含量最高,损伤15d后,剪叶4枝比对照增加36.6%,虫害4枝增加的百分率达到98.3%。剪叶4枝15d后及虫害4枝5d后,损伤25%与50%之间氨基酸总含量差异显著(P0.05),且昆虫取食4枝25%、50%、75%后松针内游离氨基酸总含量的变化趋势与剪叶处理后总氨基酸含量的变化一致,均在处理10d后呈现较高的含量,虽虫害后的氨基酸总含量高于剪叶损伤后的总含量,但二者之间差异不显著。剪叶4枝、8枝、12枝3个损伤程度后针叶内的游离氨基酸含量无显著差异,说明剪叶4枝即能超过落叶松的耐受阈值,达到防御诱导效应。两种处理下多种游离氨基酸的含量均有下降,其中8种氨基酸含量存在显著差异(P0.05),即丝氨酸、谷氨酸、甘氨酸、组氨酸、脯氨酸、半胱氨酸、赖氨酸和苯丙氨酸。表明人工模拟剪叶的损伤方式与虫害都可诱导松树氨基酸组分及含量的变化,而间接影响害虫的生长发育。     

Investigating the parameters affecting the adsorption of amino acids onto AgCl nanoparticles with different surface charges

In this paper, adsorption behaviors of typical neutral (alanine), acidic (glutamic acid) and basic (lysine) amino acids onto the surfaces of neutral as well as positively and negatively charged silver chloride nanoparticles were examined. Silver chloride nanoparticles with different charges and different water content were synthesized by reverse micelle method. The adsorptions of the above mentioned amino acids onto the surfaces of differently charged silver chloride nanoparticles were found to depend strongly on various parameters including pH of the aqueous solution, type of amino acid, water to surfactant mole ratio, and type of charges on the surfaces of silver chloride nanoparticles. It was found that the interaction of –NH₃ ⁺ groups of the amino acids with silver ion could be a driving force for adsorption of amino acids. Alanine and Glutamic acid showed almost similar trend for being adsorbed on the surface of silver chloride nanoparticles. Electrostatic interaction, hydrophobicity of both nanoparticle and amino acid, complex formation between amine group and silver ion, interaction between protonated amine and silver ion as well as the number of nanoparticles per unit volume of solution were considered for interpreting the observed results.