氨基酸混合体系的PLS分光光度法测定

本文利用亮氨酸、异亮氨酸、色氨酸、赖氨酸和苏氨酸混合物与茚三酮在 PH值 5 .2的 HAc-Na Ac缓冲溶液中发生高灵敏度的显色反应 ,建立了用偏最小二乘 (PL S)分光光度法不经分离同时测定氨基酸混合物的方法。讨论了波长范围、波长间隔对测定结果的影响 ,并同卡尔曼滤波法 (KF)和氨基酸自动分析仪结果做了比较。     

果汁饮料中甘氨酸添加剂的荧光分光光度分析

甘氨酸是生产氨基酸的基本原料,在食品工业中用作酿造、肉食加工和清凉饮料的配方,是重要的添加剂,其测定方法主要是茚三酮比色法和甲醛法。在醋酸与醋酸钠的缓冲介质中,将甘氨酸与乙酰丙酮以及甲醛按一定比例混合,在沸水浴中加热后能够发生灵敏的显色反应,曾有利用该反应进行甘氨酸测定的报道呤,试验表明该产物能够发生较强的荧光,基于此建立了一种测定甘氨酸的方法。本实验详细探讨了该反应的最佳条件以及共存离子的影响,对饮料中低浓度甘氨酸的测定有一定的意义。     

荧光光谱法测定氨基酸的新方法

在醋酸 醋酸钠缓冲介质中 ,氨基酸能猝灭壳聚糖 茚三酮体系的荧光。基于此 ,建立了一种新的荧光光谱测定氨基酸的方法 ,探讨了其反应机理及测定条件。方法的线性范围为 0mol·L- 1 ～ 1 2× 1 0 - 4 mol·L- 1 ,已应用于测定果汁饮料     

硫代硫酸钠脱除氨基酸铜络合物中铜的研究

报道了用硫代硫酸钠脱去侧链保护氨基酸铜络合物中铜离子的新方法,该方法适用于合成Nδ-苄氧羰基鸟氨酸、Nδ-叔丁氧羰基鸟氨酸、Nδ-芴甲氧羰基鸟氨酸、Nδ-乙酰基鸟氨酸、Nδ-邻苯二甲酰基鸟氨酸、Nε-苄氧羰基赖氨酸、Nε-叔丁氧羰基赖氨酸、Nε-芴甲氧羰基赖氨酸、Nε-乙酰基赖氨酸、Nε-邻苯二甲酰基赖氨酸、γ-苄基谷氨酸、β-苄基天门冬氨酸.产物用元素分析法与1H NMR法进行了表征.探讨了反应温度、时间、投料比例、溶剂对脱铜反应的影响.实验结果表明,以硫代硫酸钠作为脱铜试剂,侧链保护氨基酸铜络合物与硫代硫酸钠的物质的量比为1∶1或1∶2,60℃反应1.5～2.0h,收率与产物纯度均较高.该方法简便、高效、环境友好.     

空气整段间隔流动注射分析的应用——茶叶中α-氨基酸总量的测定

用水合茚三酮以硫酸肼还原,与氨基酸反应的空气整段间隔流动注射分析法测定茶叶中α-氨基酸总量,只需90℃、5min测定下限就可达5mg/L,回收率在97～106％,进样频率80样/h。     

荧光探剂——4-甲基-7-羟基香豆素-6-磺酰氯的合成及其荧光性能

1 引言 目前,胺类及氨基酸的荧光探剂应用得最广泛的有:丹酰氯(DNS-Cl)、邻苯二甲醛(OPA)、氯甲酸-9-苯甲酯(FMOC-Cl),它们各有利弊。4-甲基-7-羟基香豆素-6-磺酰氯(MUS-Cl)的合成已有极道,但其应用还未见报道。本文合成和鉴定了这种试剂,研究了它的荧光性能与介质的极性、pH、SAS等的关系,利用硅胶层析分离,讨论了它和氨基酸的反应情况,发现MUS-Cl可作为胺类及氨基酸荧光探针。     

高效液相色谱荧光检测法测定瓜子中的4-氨基丁酸

在众多的氨基酸中，4-氨基丁酸是一种非蛋白质类氨基酸，它在医学上是一种抑制性神经递质，由于其自身的特点，一些常规的直接测定法灵敏度较低。尽管对其测定有较多报道，但采用柱前衍生的分离测定的报道相对较少，且测定结果不很理想。本实验采用新型荧光试剂咔唑-9-乙基氯甲酸酯(CEOC)作为衍生试剂在Hyperil C18柱上分离测定了4-氨基丁酸(GABA)。结果表明，所建立的方法简单、快速，灵敏度高。     

脯氨酸和羟脯氨酸层析斑点的显色定量测定法

脯氨酸及羟脯氨酸层析斑点的显色定量至今无理想的方法,通常是用茚三酮或吲哚醌溶液显色,前者呈黄色,敏度低,很少用于定量分析,而后者虽显特异蓝色。但极不稳定,也难以作定量分析。Jepson等曾对羟脯氨酸先用茚三酮或吲哚醌溶液显色,再用Ehrlich试剂显色,呈特异紫色,但未见定量分析报导,Hrabetova等,曾用吲哚醌醋酸锌异丙醇液显色测定脯氨酸;Heathcote等用镉—茚三酮液显色测定各氨基酸层析斑点,此二种氨基酸斑点呈黄色,须在350毫微米波长比色定量,且稳定性欠佳。     

3,5,6-三-氧-甲基-D-葡萄糖与N-取代甘氨酸乙酯反应中的Amadori重排

Amadori重排是胺(包括氨基酸)与还原糖间一系列复杂反应中的很重要的一步,反应。一级胺以及二级芳香胺与还原糖反应中的Amadori 重排已有大量报道,但对涉及二级脂肪胺特别是 N-取代氨基酸的报道却为数甚少。Anet 曾报道了 N-取代甘氨酸与葡萄糖作用后,得到 Amadori 重排产物的结果,但对其作用机制及反应中间产物无详细描述。本文研究了 N-取代甘氨酸乙酯与3,5,6-三-氧-     

荧光法猝灭测定木槿叶中混合氨基酸的总量

在乙酸-乙酸钠缓冲介质中,氨基酸能猝灭壳聚糖-茚三酮体系荧光,基于此,对木槿叶中混合氨基酸进行测定,并对该方法的测定条件进行了讨论.线性范围为0.5～3.0 mmol/L,检出限为0.1 mmol/L.木槿叶干粉中游离氨基酸的质量分数为10.18%,相对标准偏差为1.3%,回收率为102.5%～94.3%.     

电化学氧化赖氨酸应用于改变碳表面荷电状态

电化学氧化赖氨酸应用于改变碳表面荷电状态;表面改性;玻碳;赖氨酸单层膜;循环伏安;静电排斥作用     

Determination of lysine in protein hydrolyzates using lysine decarboxylase from salmonella hadar

Lysine may be determined in protein hydrolyzates with the aid of lysine decarboxylase contained in cell-free extracts of Salmonella hadar grown under suitable conditions.     

膨润土吸附氨基酸研究

本文用钠、钙两种类型膨润上对四种不同性质氨基酸进行了静态吸附试验，并对膨润土吸附氨基酸有关因素进行了研究。试验证明：钙膨润土吸附氨基酸能力较强，酸处理膨润土吸附性最好，等电；点时吸附量最大。在浓度为500mg·L－1pH＝7溶液中，酸处理膨润土吸附赖氨酸可达200mmol·100g－1。     

Determination of Lysine in Nutrition Sample by Adsorption Voltammetry

Abstract

Lysine can be determined by adsorptive voltammetry after derivatization with acetaldehyde in 1.3 x 10^?2mol/ L borax-NaOH buffer solution (containing 4 x 10^?3mol/ L of CH₃CHO at pH10). The Schiff's base product of the derivation can be adsorbed on a hanging mercury electrode and reduced with peak potential of about -1.33v (vs.SCE) after 120s pre-concentration time. The derivative peak height is linearly proportional to the concentration for lysine in the range 6.0 x 10^?7-1.0 x 10^?5mol/ L. The detection limit is 4.0 x 10^?7mol/ L. Using this method, we have directly determined lysine in nutrition samples without any pre-separation step.     

赖氨酸-甲醇-1,2-萘醌-4-磺酸钠体系褪色光度法测定甲醇

赖氨酸与1,2-萘醌-4-磺酸钠在碱性条件下发生亲核取代反应,生成红褐色的产物,在该体系中加入甲醇后发生褪色反应,褪色最大波长λmax=559 nm,甲醇质量浓度在0.050～7.61 g/L范围内与吸光度降低程度呈良好线性关系,线性回归方程为A=-0.005 17-0.086 79c(g/L),线性相关系数r=0.999 6,检测限为49.5 mg/L,平均回收率为99.1%～102.6%。 用于甲醇样品测定,结果满意。     

Study of the Electrostatic Interaction of Lysine Monolayer on Glassy Carbon Electrodes Using the Electrochemical Method

A covalent modified glassy carbon electrode (GCE) with Lysine (Lys) has been fabricated via an electrochemical oxidation procedure. The electrostatic interaction of the monolayer has been investigated by cyclic voltammetry (CV) with Fe(CN)₆^3? redox probe in different concentrations of protons and different charged cations, respectively. The electrochemical method can be a new feasible method for the study of electrostatic interaction of the monolayer.     

Aggregation Properties of Sodium Hyaluronate with Alkanediyl-alpha,omega-bis(dimethylalkylammonium Bromide) Surfactants in Aqueous Sodium Chloride Solution

Lysine, which is an amino acid with a basic side group, is present in biological fluids and its role in the biological calcification process was investigated. It was found to inhibit the crystal growth rate of hydroxyapatite (HAP), in solutions supersaturated only with respect to this calcium phosphate salt and this rate reduction was attributed to adsorption and further blocking of the active growth sites on the crystal surface. The crystallization kinetics were interpreted in terms of the Langmuir adsorption model. The apparent order of the crystallization reaction was found to be n=2, suggesting a surface diffusion controlled spiral growth mechanism. Kinetic results of HAP crystallization were obtained using the constant composition method where the concentration of the reactants is kept constant during the course of the crystal growth experiment. Copyright 2000 Academic Press.     

Aggregation properties of diacyl lysine surfactant compounds: hydrophobic chain length and counterion effect

In this paper, we report on the study of aqueous solution and aggregation properties of diacyl Lysine surfactant salts with several surfactant counterions at a fixed hydrophobic chain length. They present a critical micellar concentration nearly independent of the counterion. The area per surfactant molecule is around 1.3 nm (2) also independent of the counterion. We have also studied the dry state crystallization of these surfactant salts. We show that small counterion systems tend to form bicontinuous cubic structures and that the increase in counterion size tends to form lamellar structures. We have compared this behavior with the dry state crystallization of the diacyl Lysine surfactants as a function of hydrophobic chain length. For long hydrophobic chains, the crystal structure is lamellar, while for intermediate, length is cubic. Among the structures studied, the one with the shortest chain length crystallizes in a hexagonal inverse phase.     

Lysine production in continuous culture

Applied Biochemistry and Biotechnology - Lysine is an essential amino acid that is widely used as a feed additive. Many animal feeds are deficient in lysine, so the lysine, as well as other amino...     

Immobilization of Antibodies on Magnetic Carbonaceous Microspheres for Selective Enrichment of Lysine‐acetylated Proteins and Peptides

Lysine acetylation is a dynamic and reversible modification, which has been proved to be a key posttranslational modification in cellular regulation. However, the low amounts of the acetylated proteins could hardly be detected before enrichment. In this study, for the first time, antibody‐immobilized magnetic carbonaceous microspheres were developed for selective enrichment of acetylated proteins and peptides. At first, standard proteins composed of acetylated bovine serum albumin, myoglobin, α‐casein and ovalbumin were used as model proteins to verify the enrichment efficiency. Then, the synthesized peptide was employed to confirm the selectivity of the method. Besides, the antibody‐immobilized magnetic particles were successfully applied to analyze mouse mitochondrial proteins. After database search, 29 acetylated sites in 26 proteins were identi?ed.