Free Radicals Developed in the Amino-Garbonyl Reaction of Sugars with Amino Acids

GA_l5, GA₃, GA₅, GA₁₉, GA₂₀ and GA₂₃ were identified by GC-MS in the acidic ethyl acetate-soluble fraction from the seeds of sweet potato (Ipomoea batatas Lam.). GA₁₉ and GA₂₃ were major GAs in the mature seeds, their contents being about 200 and 160 μg/kg fresh weight, respectively, while those of GA₁₉ and GA₂₃ in immature seeds were below 100 μg/kg fr. wt. The occurrence of glycosyl conjugates of GA₃, GA₅, GA₈, GA₁₇, GA₁₉, GA₂₀, GA₂₃ and GA₄₄ in the butanol fraction from mature seeds was shown by GC/MS analysis after enzymatic hydrolysis.

Besides the endogenous GAs in sweet potato, those in immature seeds of several other Convolvulaceae plants were investigated. The species of endogenous GAs were discussed in terms of chemotaxonomy.     

Amino Acids from Heterodera glycines

Amino acids emitted and extracted from surface-sterilized larvae and adults of Heterodera glycines were identified by paper chromatography and quantitatively analyzed by column chromatography. Five amino acids (alanine, aspartic acid, glutamic acid, glycine and serine) were emitted by H. glycines larvae and eight others (asparagine, glutamine, leucine/isoleucine, lysine, methionine sulfoxide, threonine, tyrosine, valine/methionine) were found in extracts from crushed larvae.In addition to the amino acids emitted or extracted from larvae, four others were emitted by adults (γ-aminobutyric acid, histidine, phenylalanine, and proline). Four different amino acids (arginine, cystathionine, hydroxyproline, and ornithine) were found only in the extract from crushed adults. Greater quantities of alanine, aspartic acid and glycine were emitted than could be detected in nematode extracts suggesting selective emission.Subsamples of nematode populations were taken from growing plants 19, 26, 33, and 40 days after inoculation and extracted to determine whether changes in specific amino acid content correlated with aging. Proline content shifted most, increasing from 4.1% to 21.5% of the total amino acid complement from the 19th to the 40th days.     

Biosynthesis of Amino Acids from Hydrocarbons

Nine strains of bacteria, capable of synthesising amino acids from hydrocarbons, have been identified. Pseudomonas arvilla, Ps. fluorescens and Micrococcus ureae, previously reported as hydrocarbons assimilators, were found capable of synthesising amino acids. Pseudomonas taetrolens, Bacillus cereus var. mycoides, Bacillus subtilis and Bacillus sphaericus also synthesised amino acids from hydrocarbons.     

Synthesis of Amino Acids from Hydrocarbons

Isolation of microorganisms capable of synthesising amino acids, utilizing hydrocarbons, has been reported. These microorganisms were isolated from soil samples by selective culture techniques. 91 strains were found capable of producing amino acids in the broth. Different amino acids and their maximum yield obtained were glutamic acid 160 mg/1; leucine 90.0 mg/1; isoleucine 40.0 mg/1; valine 105.0 mg/1; methionine 25.0 mg/1; tryptophan 2.5 mg/1; arginine 70.0 mg/1; and histidine 10.0 mg/1.     

老龙皮总氨基酸的提取工艺研究

通过单因素选择和正交设计法,以老龙皮总氨基酸含量为指标,分别对乙醇浓度、料液比、提取温度、提取时间等因素进行考查,优选老龙皮总氨基酸的最佳提取条件。结果显示料液比对总氨基酸提取率影响最大,最佳提取条件为60%乙醇作提取液,料液比(W/V)为1∶20,在70℃提取3 h。     

板蓝根热加工过程中氨基酸组分分析

利用氨基酸自动分析仪对板蓝根的新鲜植物组织和不同加工程度的板蓝根药材中的总氨基酸和游离氨基酸含量进行测定。结果表明:板蓝根的新鲜植物组织和不同加工程度的板蓝根药材氨基酸在含量上有明显差别。结论为:不同加工程度的板蓝根药材中氨基酸含量差别明显,其中碱性氨基酸含量的差别尤其显著,该差异可能是由于加工过程中发生美拉德反应造成的。     

13CMFA过程中GC-MS分析菌体蛋白氨基酸的13C标记丰度

基于13C标记的代谢通量分析(13CMFA)由于具有准确性和应用性已成为国际上代谢工程研究的热点,其中一个至关重要的问题就是分析菌体蛋白氨基酸的13C标记丰度信息。用含20%全标记葡萄糖（［U-13C］）和80%天然葡萄糖的合成培养基喂养维生素B12生产菌Pseudomonas denitrifican,然后在稳态条件下取20mg带13C标记菌体用1ml 6mol/L盐酸95℃水解24h得到带13C标记的菌体蛋白氨基酸;氨基酸经分离、浓缩、真空干燥、MBDSTFA衍生化后得到的TBDMS衍生物可以用气相色谱-质谱(GC-MS)进行分析,最后分析质谱图得到15种菌体蛋白氨基酸的13C标记丰度信息。成功获得菌体蛋白氨基酸13C标记丰度信息的实验方法和样品处理技术,为13CMFA在国内进一步发展提供了参考意义。     

龙眼肉干制过程氨基酸组分分析

利用氨基酸自动分析仪分别测定加工前后的龙眼肉中的总氨基酸和游离氨基酸含量。结果,干制前后龙眼肉的氨基酸种类没有差别,但含量有明显差别,多数氨基酸的含量在干制后明显下降。结论:除丙氨酸和甲硫氨酸外,干制后的龙眼肉中的总氨基酸和游离氨基酸含量比干制前有明显下降,其中以碱性、酸性氨基酸含量的下降尤其显著。该差异可能是由于干制过程中发生美拉德反应造成的。     

Permeases Recycle Amino Acids Resulting from Autophagy

Autophagy is a major survival mechanism for eukaryotes to recycle cellular nutrients during stress conditions (such as nutrient limitation, or the accumulation of damaged organelles). We recently revealed a molecular mechanism by which Atg22 recycles amino acids to link the degradative and recycling functions of autophagy. Atg22 is not directly required for autophagic body breakdown, in contrast to previously reported data. Instead, we found that Atg22, Avt3 and Avt4 are partially redundant vacuolar effluxers, which mediate the efflux of leucine and other amino acids resulting from autophagy.

Addendum to:

Atg22 Recycles Amino Acids to Link the Degradative and Recycling Functions of Autophagy

Zhifen Yang, Ju Huang, Jiefei Geng, Usha Nair and Daniel J. Klionsky

Mol Biol Cell 2006; Oct. 4     

栀子花氨基酸成分的分析测定

目的:研究栀子花中氨基酸成分的种类及含量,为栀子花的开发利用提供科学依据.方法:将栀子花粉末用盐酸恒温水解处理,水解液用氨基酸自动分析仪测定.结果:栀子花含有17种氨基酸,其中7种人体必需氨基酸的质量分数达26.7mg·g-1,占总量的36.6％.结论:栀子花中氨基酸质量分数达7.3％,是一种很有开发价值的药食两用植物...     

海南青牛胆中游离氨基酸的分析

对海南青牛胆(Tinospora hainanesis H.S.Lo et Z.X.Li)藤茎中游离氨基酸进行了测定。结果表明,海南青牛胆中游离氨基酸种类极其丰富,其含量总游离氨基酸为0．27％,人体必需氨基酸占总游离氨基酸选75％,精氨酸含量最高,为0．0909％。     

Revisiting the Ramachandran plot from a new angle

The pioneering work of Ramachandran and colleagues emphasized the dominance of steric constraints in specifying the structure of polypeptides. The ubiquitous Ramachandran plot of backbone dihedral angles (φ and ψ) defined the allowed regions of conformational space. These predictions were subsequently confirmed in proteins of known structure. Ramachandran and colleagues also investigated the influence of the backbone angle τ on the distribution of allowed φ/ψ combinations. The “bridge region” (φ ≤ 0° and −20° ≤ ψ ≤ 40°) was predicted to be particularly sensitive to the value of τ. Here we present an analysis of the distribution of φ/ψ angles in 850 non-homologous proteins whose structures are known to a resolution of 1.7 Å or less and sidechain B-factor less than 30 Ų. We show that the distribution of φ/ψ angles for all 87,000 residues in these proteins shows the same dependence on τ as predicted by Ramachandran and colleagues. Our results are important because they make clear that steric constraints alone are sufficient to explain the backbone dihedral angle distributions observed in proteins. Contrary to recent suggestions, no additional energetic contributions, such as hydrogen bonding, need be invoked.     

海藻非蛋白质氨基酸的研究进展

海藻非蛋白质氨基酸是海藻中一类重要的生物活性物质,大多具有清热、解毒、驱虫、降血压、防癫痫等功能,本文主要对海藻非蛋白质氨基酸的概念、分类、生物合成、生物功能及其应用、检测分析、分离提取等做一概述,为更好的开发利用这类生物活性物质提供参考.     

地黄炮制过程氨基酸组分分析

利用氨基酸自动分析仪分别测定加工前后地黄中的总氨基酸和游离氨基酸质量分数。分析、比较炮制前后地黄的氨基酸成分变化。炮制前后地黄的氨基酸种类及含量有明显变化,多数氨基酸的含量在炮制后明显下降甚至消失。结论:炮制前后的地黄中氨基酸质量分数差别明显,其中碱性氨基酸质量分数的差别尤其显著,该差异可能是由于炮制过程中发生美拉德反应造成的。     

制革废弃物中氨基酸的提取和分离

综述了制革废弃物中氨基酸的提取及分离技术的发展状况 ,包括如何从制革厂回收的毛中提取胱氨酸等氨基酸以及如何从皮屑和铬革屑中提取脯氨酸等各种氨基酸的方法     

红萼月见草种子脂肪权与氨基酸的分析

红萼月见草 (ＯｅｎｏｔｈｅｒａｅｔｙｔｈｒｏｓｅｐａｌａＢｏｒｂ .)为柳叶菜科植物 ,刘国声等[1] 曾报道该植物花挥发油成分研究 ,高雅琴[2 ] 报道其它同属六种栽培植物月见草种子的化学成分分析 ;但未见有该种植物的脂肪酸与氨基酸的分析报道。因月见草种子油具有多种生理活性 ,月见草油中的γ 亚麻酸能以较小的剂量即产生显著的抗血栓、降血脂、抗炎、抗心律不齐、减肥、抑制癌细胞生长等生理活性 ,目前国内外广泛用于医药、保健品、食品的生产[3～ 6 ] 。为了满足需要 ,扩大资源 ,特进行引种栽培的红萼月见草种子脂肪酸与氨基酸的分…     

Effects of Dietary Amino Acids on Brain Amino Acids and Transmitter Amines in Rats with a Portacaval Shunt

The etiologic relationship between disturbances in metabolism of amino acids and amines and hepatic coma was investigated by examining the effects of diets containing various mixtures of amino acids on brain amine metabolism in rats with a portacaval shunt, using a method for simultaneous analysis of amino acids and amines. Rats with a portacaval shunt were fed on four different amino acid compositions with increased amounts of various amino acids suspected to be etiologically related to hepatic coma, such as methionine, phenylalanine, tyrosine, and tryptophan. The animals were killed 4 weeks after operation. During the experimental period, these animals did not become comatose, but exhibited various behavioral abnormalities. Marked increase in the plasma and brain levels of the augmented amino acids, especially methionine and tyrosine, were observed in rats with a portacaval shunt. Brain noradrenaline, dopamine, and serotonin levels were significantly decreased when the brain tyrosine level was increased. These results indicate that in rats with a portacaval shunt the dietary levels of amino acids greatly influence the brain levels of both amino acids and transmitter amines.     

从鸡毛中提取复合氨基酸的研究

运用正交实验研究了以鸡毛为原料硫酸水解生产复合氨基酸的水解条件。结果表明 :硫酸浓度为 8mol·L- 1 ,鸡毛质量 (g)与硫酸体积 (mL)之比为 1∶2 .5 ,水解时间 10h ,其水解率可达 5 5 .2 3%。得到的固体氨基酸质量分数为 95 .31%。     

支链氨基酸对运动大鼠氨基酸代谢和运动能力的影响

观察了支链氨基酸(BCAA)对大鼠运动能力和血清游离氨基酸代谢的影响。实验用21只雄性wistar大鼠,随机分为3组:正常组、游泳对照组和游泳补充BCAA组。2个运动组每天游泳训练1h,10天后游泳6h,观察补充BCAA对大鼠游泳运动能力和血清游离氨基酸水平的影响。实验结果表明,补充BCAA可明显提高大鼠游泳存活率,抑制血清中必需氨基酸、非必需氨基酸和总氨基酸水平升高,游泳运动后大鼠的血清中乳酸和LDH的升高幅度有所降低,抑制骨骼肌LDH活力的下降。说明补充BCAA可明显提高大鼠的运动能力,减少运动造成的蛋白质分解     

Pyrolysis of Sulfur-containing Amino Acids

Sulfur-containing amino acids (l-cysteine, l-cystine and dl-methionine) were pyrolyzed. From pyrolyzed cysteine and cystine were identified 7~8 volatile compounds including 2-methylthiazolidine which is considered to be the product of the reaction of acetaldehyde with mercaptethylamine, and from pyrolyzed methionine were identified 11 volatiles. At the same time, besides these volatile compounds, alanine, cystine and isoleucine, and alanine, isoleucine and methionine were detected in the pyrolyzed products of cysteine and cystine, respectively, but no amino acid was detected from that of methionine. The mixture of seven identified volatiles generated from l-cystine developed a pop-corn like aroma with a roasted sesame like one, and methylmercaptane seemed to be the main contributor to the pickled radish like odor produced from pyrolysis of dl-methionine. Degradation schemes of cystine and methionine were proposed.