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.     

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.     

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。     

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…     

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     

Enzymatic Production of Amino Acids

Abstract

Insects have extremely sensitive systems of olfaction. These systems have been explored as potential sensors for odourants associated with forensics, medicine, security, and agriculture application. Most sensors based on insect olfaction utilize associative learning to “program” the insects to exhibit some form of behavioural response to a target odourant. To move to the next stage of development with whole-insect programmable sensors, an examination of how odourants are captured, processed and used to create behaviour is necessary. This review article examines how the neurophysiological, molecular, genetic and behavioural system of olfaction works and how an understanding of these systems should lead the way to future developments in whole-insect programmable sensors.     

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.     

活性氨基酸农药

介绍了活性氨基酸作为农用杀菌剂,杀虫剂、除草剂以及生长调节剂的结构与应用,它为解决环境保护问题展示了新的前景。     

Sulphur-Containing Amino Acids Modulate Noradrenaline Release from Hippocampal Slices

Abstract: The l - and d -enantiomers of the sulphur-containing amino acids (SAAs)—homocysteate, homocysteine sulphinate, cysteate, cysteine sulphinate, and S-sulphocysteine—stimulated [³H]noradrenaline release from rat hippocampal slices in a concentration-dependent manner. The relative potencies of the l -isomers (EC₅₀ values of 1.05–1.96 mM) were of similar order to that of glutamate (1.56 mM), which was 10-fold lower than that of NMDA (0.15 mM), whereas the d -isomers exhibited a wider range of potencies (0.75 to >5 mM). All stimulatory effects of the SAAs were significantly inhibited by the voltage-sensitive Na⁺ channel blocker tetrodotoxin (55–71%) and completely blocked by addition of Mg²⁺ or Co²⁺ to the incubation medium. All SAA-evoked responses were concentration-dependently antagonized by the selective NMDA receptor antagonist d -(?)-2-amino-5-phosphonopentanoic acid (IC₅₀ values of 3.2–49.5 µM). 6-Cyano-7-nitroquinoxaline-2,3-dione (CNQX), a non-NMDA receptor antagonist, at 100 µM inhibited the [³H]noradrenaline release induced by glutamate and NMDA (65 and 76%, respectively) and by all SAAs studied (65–85%), whereas 10 µM CNQX only inhibited the effects of S-sulpho-l -cysteine and l - and d -homocysteate (33, 32, and 44%, respectively). However, the more selective AMPA/kainic acid receptor antagonist 6-nitro-7-sulphamoylbenzo(f)quinoxaline-2,3-dione (100 µM), which did not antagonize the [³H]noradrenaline release induced by glutamate and NMDA, reduced only the S-sulpho-l -cysteine-evoked response (25%). Thus, the stimulation of Ca²⁺-dependent[³H]noradrenaline release from hippocampal slices elicited by the majority of the SAAs appears to be mediated by the NMDA receptor.     

利用羊胎盘下脚料制备复合氨基酸的研究

对以羊胎盘下脚料制备复合氨基酸进行了分析研究。结果表明 ,产品中含有多种微量元素和 18种氨基酸 ,有很大的开发价值和经济效益。     

Prediction of Physical-Chemical Properties of Amino Acids from Genetic Code

Using the crystal basis model of the genetic code, a set of relations between the physical-chemical properties of the amino acids are derived and compared with the experimental data. A prediction for the not yet measured thermodynamical parameters of three amino acids is done.     

The Mass Spectra of Thiohydantoins Derived from Some Amino Acids

One of the bound forms of vitamin B₆ occurring in rice bran was isolated in a faintly yellowish syrup by repeating ion-exchange and paper-partition chromatographic techniques. The behaviors of the isolate on thin-layer and Aminex A–5 column chromatograms were coincident with those of synthetic pyridoxine-β-d-glucoside which was obtained by Königs-Knorr condensation of α⁴,3-O-isopropylidene pyridoxine and 2,3,4,6-tetra-O-acetyl-α-d-glucopyranosyl bromide. On acid hydrolysis, the isolate gave pyridoxine and glucose. Glucose was proved to bind to the 5-hydroxymethyl group of pyridoxine, because the isolate did not react with 2,6-dichloroquinone chlorimide in the presence of boric acid. An equimolar amount of pyridoxine and d-glucose was produced with an equivalent consumption of the isolate by the action of β-glucosidase. No essential difference between the isolated and synthetic preparations could be detected in UV- and NMR-spectral features. Thus, the chemical structure of the isolate was identified as 5′-O-(β-d-glucopyranosyl) pyridoxine.     

Stereochemistry and Reactions of Aziridinyl- phosphinothionates Derived from Amino Acids

Aziridinylphosphinothionates were prepared from optically active ethyl hydrogen phenylphos- phonothionates and l-bromo-2-alkanamines derived from leucine or valine. The aziridine ring was opened by the action of some nucleophiles. Refluxing the aziridinylphosphinothionates in acetone with sodium iodide caused hydrolysis accompanied by the rearrangement of the sulfur atom to give β -mercaptoethylphosphonamidates. The reaction mechanism was discussed with stereochemical considerations. The insecticidal activity of the products was also examined.     

Neuroligand-Evoked Calcium-Dependent Release of Excitatory Amino Acids from Cultured Astrocytes

Abstract: The release of excitatory amino acids (EAAs) from neuron-free cultures of neocortical astrocytes was monitored using HPLC. The neuroligand bradykinin caused a dose-dependent receptor-mediated increase in release of the EAAs glutamate and aspartate from type 1 astrocyte cell cultures obtained from rat cerebral cortex. Removal of calcium from the extracellular fluid prevented the bradykinin-induced release of EAAs from astrocytes. The addition of the calcium ionophore ionomycin caused a calcium-dependent release of EAAs. Inhibitors of the glutamate transporters p -chloromercuriphenylsulfonic acid, l - trans -pyrrolidine-2,4-dicarboxylate, and dihydrokainate failed to impair the ability of bradykinin to stimulate glutamate release from astrocytes. α-Latrotoxin, an active compound of black widow spider venom, caused a significant increase of the release of glutamate in calcium-containing saline. In calcium-depleted saline, α-latrotoxin produced an initial increase in the concentration of glutamate followed by a decline in the concentration of glutamate indicating stimulation of exocytosis coupled with low calcium-induced inhibition of endocytosis. Taken together, these data suggest that astrocytes may release neurotransmitter through a mechanism that is similar to the neuronal secretory process. Given the important role of glutamate in the induction of long-term potentiation, learning, memory, and excitotoxicity, it will be important to determine external signals that control both the uptake and release of glutamate by astrocytes.