华南主要野生蔬菜氨基酸含量及营养价值评价

通过分析华南地区八种主要野生蔬菜的氨基酸含量,对其氨基酸营养进行评价,并和菜心进行对比,发现八种野生蔬菜除不含胱氨酸外,其它氨基酸含量均很丰富,是有利用人体氨基酸营养平衡的天然绿色食品。     

神经肽注射液氨基酸组成分析及含量测定方法的研究

本文采用具有高灵敏度的高效液相色谱法（ＨＰＬＣ）对神经肽注射液中的氨基酸组成及含量进行了测定,结果表明该注射液中含有１３种游离氨基酸（２９．９４ｍｇ／１００ｍｌ）和大量的低分子多肽（２１１．１６ｍｇ／１００ｍｌ）。同时,本文也建立了简便快速测定神经肽注射液中溶质含量的紫外分光光度法（ＵＶＳ）。试验结果反映了产品的内在质量,为建立质量控制方法提供了依据。     

5种中草药的营养价值测定

为探讨中草药饲料添加剂的作用机制,本研究测定了黄芪、刺五加、党参、山楂和丹参中常规营养成分和氨基酸的含量。结果显示,中草药中的蛋白质和氨基酸特别是必需氨基酸含量丰富,黄芪和丹参除蛋氨酸、酪氨酸和脯氨酸外的其它14种氨基酸的含量均相对较高,特别是黄芪中赖氨酸、天门冬氨酸和谷氨酸的含量分别高达1．078％、1．644％和1．368％。本结果为进一步研究中草药资源在动物生产中的应用提供了一定的科学依据。     

黄芪叶中黄芪甲苷的含量测定

目的 :测定黄芪叶中黄芪甲苷的含量 ,寻找提取黄芪甲苷的新药源。方法 :本实验以黄芪甲苷为标准品 ,采用薄层色谱—分光光度法测定黄芪叶中黄芪甲苷的含量。结果 :叶中的黄芪甲苷含量是根中的 2 .8倍。结论 :黄芪叶有潜在的开发价值     

人工冬虫夏草的氨基酸含量及其营养价值评价

目的为明确人工和野生冬虫夏草在氨基酸方面的差异,并为进一步开发利用人工冬虫夏草提供理论依据,对室内全人工培殖冬虫夏草和产自四川康定的野生冬虫夏草的氨基酸营养价值进行分析评价。方法用日立L-8800型全自动分析仪检测氨基酸含量并根据FAO/WHO的氨基酸评分标准模式和鸡蛋蛋白模式进行氨基酸营养价值评价。结果人工冬虫夏草氨基酸种类齐全,其全草氨基酸总量高于产自康定的野生冬虫夏草;其全草的鲜味氨基酸高于产自康定的野生冬虫夏草;其全草必需氨基酸总量低于产自康定的野生冬虫夏草。人工冬虫夏草必需氨基酸与氨基酸总量的比值高于WHO/FAO评分模式而低于鸡蛋蛋白模式。结论人工冬虫夏草氨基酸不仅种类组成合理,而且具有较高的营养价值。这一结果为人工冬虫夏草的进一步开发利用提供了理论基础。     

鸡冠花叶蛋白质营养价值的评价研究

应用模糊识别法和氨基酸比值系数法,分别以鸡蛋蛋白南为标准蛋白,以ＷＨＯ／ＦＡＯ氨基酸参考模式为评价标准,对３种鸡冠花叶蛋白质营养价值进行了全面评价,并与１０种常见叶菜蛋白进行对照比较。结果表明,３种鸡冠花叶（干品）蛋白质含量为２３．７％￣２７．４％,蛋白质中氨基酸种类齐全,其含量为８３．４７％￣８６．９４％,必需氨基酸（ＥＡＡ）占总氨基酸量的４０．２％￣４１．７％,第一限制性氨基酸为含硫氨基酸（Ｍ     

4种小檗科植物叶片的蛋白质及氨基酸组成分析

蛋白质和氨基酸是植物体内重要的营养物质,研究药用植物的蛋白质和氨基酸组成对药用植物资源的合理开发和综合利用具有重要意义,但目前对药用植物次生代谢物的研究较为广泛（如黄酮类化合物[1-2],而对其初生代谢物的研究相对较少[3-4]。     

Protein content and amino acid composition of cassava leaf

On the basis of leaf dry wt, the protein content of six varieties of cassava varied from 29.3 to 38.6% and the estimated leaf protein production ranged from 242 to 953 kg per ha. On the basis of fr. wt of leaf, the total amino acids ranged from 8.42 to 9.4% while the essential amino acids averaged 4.21% and the sulphur-containing amino acids only 0.25%. The amino acid composition profiles for the six varieties was similar.     

决明子营养价值分析及蛋白提取工艺研究

以大决明子为原材料,基于氨基酸比值系数法,对决明子的营养价值进行了分析;并以碱性缓冲液为提取剂,进行决明子蛋白提取工艺研究,探讨了缓冲液浓度及pH值、料液比、浸泡时间对蛋白提取率的影响,最后用正交试验确定大决明子蛋白的最佳提取工艺。结果表明决明子的营养价值高于大豆和紫花苜蓿,与南瓜接近略低于鸡蛋;提取工艺条件最佳为50 mmol/L、pH值=8.0的KH2PO4-NaOH缓冲液,料液比1 g：50 mL,浸泡提取时间12h。此条件下决明子蛋白的提取率为93.3%。     

蛋白核小球藻粉的蛋白质、氨基酸含量及营养价值评价

对蛋白核小球藻粉主要营养成分的分析结果表明,其蛋白质含量为63.60%,18种氨基酸总量为55.95%,8种必需氨基酸含量为23.35%,氨基酸分(AAS)为64.3,蛋氨酸+胱氨酸为第一限制性氨基酸。小球藻粉营养成分全面,是优良的单细胞蛋白源。     

干旱半干旱地区生物结皮层藓类植物氨基酸和营养物质组成特征及适应性分析

通过对生长在干旱-半干旱地区的藓类体内的氨基酸组成及含量变化、营养元素含量变化和可溶性糖含量变化及藓类结皮土壤相应营养元素含量变化的分析,以揭示藓类的营养组成特征及对环境的适应性机制。研究样地选择在内蒙古鄂尔多斯高原的典型草原区和宁夏腾格里沙漠南缘的草原化荒漠区。通过实验,从藓类植物体内检测出17种氨基酸,表明其体内的氨基酸组成大部分与高等植物相同,其中天门冬氨酸、谷氨酸、丙氨酸、亮氨酸和精氨酸的含量最高,约占总氨基酸的50%。脯氨酸含量在所有氨基酸中处于较低水平,平均只占氨基酸总量的3.12%。草原化荒漠区与典型草原区分布真藓平均总氨基酸含量均大于土生对齿藓,两地区间真藓有10种氨基酸(包括脯氨酸)含量有显著性均数差异(p<0.05),而土生对齿藓只有脯氨酸有显著性差异(p<0.05)。赖氨酸、精氨酸含量在两个地区各种藓类体内有相对稳定的含量,没有显著差异,而脯氨酸的含量在同一地区没有显著的差异,但在不同地区却有显著性差异。藓类体内营养元素显著高于结皮层土壤,表明苔藓植物有很强的元素富集能力,其中N含量最高,P含量最低。不同种类植物体内营养元素Ca、Mg、K的含量存在差异,表明藓类植物对金属营养元素有很强的选择吸收能力。元素相对利用能力(植物/土壤),K最大,P最小,Ca、Mg因种类不同存在差异。N/P比率在草原化荒漠区分别为真藓10.25,刺叶赤藓13.59,土生对齿藓15.78;在典型草原区分别为真藓11.91,土生对齿藓10.55,盐土藓11.37,可知N、P在干旱区不是藓类植物生长的限制因子。元素之间的相关分析表明N和P,Ca和Mg明显相关(p<0.05),而K和Ca、Mg之间则显著负相关(p<0.01),表明K和Ca、Mg之间存在制约关系。可溶性糖和脯氨酸含量分析表明,随降雨量增加二者含量明显呈现递减趋势,说明脯氨酸、可溶性糖的含量与苔藓植物的抗旱性有一定的关系。     

Screening and development of enzymes for determination and transformation of amino acids

ABSTRACT

The high stereo- and substrate specificities of enzymes have been utilized for micro-determination of amino acids. Here, I review the discovery of l-Phe dehydrogenase and its practical use in the diagnosis of phenylketonuria in more than 5,400,000 neonates over two decades in Japan. Screening and uses of other selective enzymes for micro-determination of amino acids have also been discussed. In addition, novel enzymatic assays with the systematic use of known enzymes, including assays based on a pyrophosphate detection system using pyrophosphate dikinase for a variety of l-amino acids with amino-acyl-tRNA synthetase have been reviewed. Finally, I review the substrate specificities of a few amino acid-metabolizing enzymes that have been altered, using protein engineering techniques, mainly for production of useful chemicals, thus enabling the wider use of natural enzymes.     

Prediction of protein secondary structure content using amino acid composition and evolutionary information

Knowing protein structure and inferring its function from the structure are one of the main issues of computational structural biology, and often the first step is studying protein secondary structure. There have been many attempts to predict protein secondary structure contents. Previous attempts assumed that the content of protein secondary structure can be predicted successfully using the information on the amino acid composition of a protein. Recent methods achieved remarkable prediction accuracy by using the expanded composition information. The overall average error of the most successful method is 3.4%. Here, we demonstrate that even if we only use the simple amino acid composition information alone, it is possible to improve the prediction accuracy significantly if the evolutionary information is included. The idea is motivated by the observation that evolutionarily related proteins share the similar structure. After calculating the homolog-averaged amino acid composition of a protein, which can be easily obtained from the multiple sequence alignment by running PSI-BLAST, those 20 numbers are learned by a multiple linear regression, an artificial neural network and a support vector regression. The overall average error of method by a support vector regression is 3.3%. It is remarkable that we obtain the comparable accuracy without utilizing the expanded composition information such as pair-coupled amino acid composition. This work again demonstrates that the amino acid composition is a fundamental characteristic of a protein. It is anticipated that our novel idea can be applied to many areas of protein bioinformatics where the amino acid composition information is utilized, such as subcellular localization prediction, enzyme subclass prediction, domain boundary prediction, signal sequence prediction, and prediction of unfolded segment in a protein sequence, to name a few.     

Simultaneous analysis of enantiomeric composition of amino acids and N-acetyl-amino acids by enantioselective chromatography

Among the three chiral columns, CHIROBIOTIC T, CHIRLPAK WH, and CHIRALCEL OD-R, tested for the separation of racemic amino acids and N-acetyl-amino acids, only CHIROBIOTIC T chiral column which is based on covalently bonded amphoteric glycopeptide, teicoplanin, as the stationary phase ligand could be successfully developed to enantiomerically separate racemic amino acids and N-acetyl amino acids simultaneously. This method can be used to determine the enantiomeric composition of amino acids and N-acetyl-amino acids in the catalysis of D-aminoacylase or L-aminoacylase and the conversion rate of N-acylamino acid racemases.     

4种野生蔬菜的氨基酸含量及其营养价值评价

野生蔬菜具有独特的口味,丰富的营养,有些还具有防病治病的功能,对人体有良好的保健作用.白子菜[Gynura divaricata (L.) DC.]茎叶有消热、舒筋及止血祛瘀的作用,用于镇咳、风湿性关节痛、骨折、创伤止血,痈肿疮疥等症,在民间还作抗癌草使用[1].红凤菜(Gynura bicolor DC.)茎叶有活血止血,解毒消肿的功效,治痛经,血崩,咳血,创伤出血,溃疡久不收口[2].诸葛菜[Orychophragmus violaceus (L.) Schulz]作为野生蔬菜在江苏、安徽民间有很长的食用历史,测定结果表明,该种含有黄酮类化合物[3].马齿苋(Portulaca oleracea L.)具有清热解毒、消炎、利尿、消肿的功效,民间还用于白发症、糖尿病、心血管疾病的治疗[4],中国卫生部将它列为药食同用的植物.     

Gas chromatographic determination of total amino acids and protein in sediments using the ninhydrin-CO2 reaction

A sensitive modification of the ninhydrin-CO₂ method involving the gas chromatographic determination of the total protein and amino acid content of sediment is described. The method gives a linear response over the amino acid concentration range 10^–5 M to 4 × 10^–2 M. It can be used for whole sediment, hydrolysates and interstitial water. The performance of the method is compared with the fluorescamine method for primary amines.