Methionine is an alpha amino acid used in protein synthesis. In human beings methionine is a vital amino acid not synthesized in the human body and must therefore be ingested. Methionine in the human body is used to improve skin elasticity and tone, tissue growth and repair, and keratin systems such as hair and nails. As a detoxifying agent methionine chelates heavy metals, while the sulfur in it protects cells. L-Methionine is an enantiomerically active amino acid used in the body.
Methionine’s importance in biological systems allows it a great deal of useful applications. A major component of cell culture media, it can be used for the manufacture of monoclonal antibodies and recombinant proteins. Methionine also functions as an intermediate in the biosynthesis of phospholipids, cysteine, carnitine, taurine, cysteine and lecithin. L-Methionine has been used as a reagent in the creation of anti-cancer phosphate analogs and 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate (AQC) for determination of amino acids in foods. When reacted with the methionine adenosyltransferase enzyme L-methionine produces S-adenosyl-L-methionine, a cosubstrate used in anabolic reactions in the body. S-adenosyl-L-methionine has applications as both a potential antidepressant and a protector of alcohol damages in the liver.
In other applications, methionine functions as a reagent and with metals in non-biological applications, L-methionine in particular has been used with metals to form photosensitizers and ligands for transition metal catalyzed bond forming reactions. [11C]L-Methionine has also been used in Positron Emission Tomography of brain tumors for diagnostic purposes.
Product SpecificationsL-Methionine;Methionine
Formula: C5H11NO2S
MW: 149.21 g/mol
Storage/Handling: Store at roomtemperature.
PubChem Chemical ID: 6137
GoldBio活体成像技术:早在1999年由美国哈佛大学Weissleder博士率先提出了分子影像学(molecularimaging,MI)的概念,即应用影像学的方法对活体状态下的生物过程进行细胞和分子水平的定性和定量研究。活体成像便是基于分子影像学孕育而生的,通过这个成像系统,可以观测活体动物体内肿瘤的生长及转移,感染性疾病的发展进程,特定基因的表达等生物学过程。活体成像技术主要采用生物发光(bioluminescence)与荧光(fluorescence)两种技术。★生物发光是用荧光素酶基因标记细胞或DNA。★荧光技术则采用荧光报告基团(GFP、RFP,Cyt及dyes等)进行标记。★这一技术对肿瘤微小转移灶的检测灵敏度极高,不涉及放射性物质和方法,非常安全。操作极其简单、所得结果直观、灵敏度高。
活体成像两种检测技术介绍活体成像特点优点缺点生物发光检测bioluminescence★荧光素酶(Luciferase)对基因、细胞和活体动物进行标记;★荧光素酶催化底物(例如荧光素钾盐)反应后,会产生化学发光。这种光是由化学反应而来,不需要激发光;★标记方法是通过克隆技术,将荧光素酶的基因插入到预期观察的细胞染色体内,通过对克隆细胞进行筛选,培养出能稳定表达荧光素酶的细胞株。再将细胞株转移至特定的小鼠体内形成模型。★特异性强,无自发荧光;★高灵敏度,在体内可检测到几百个细胞,检测的深度在3-100px;★定量精确 ★信号较弱,检测时间较长;★仪器精密度要求较高;★细胞或基因需要转基因标记;★不可用于人体,不适用于抗体、多肽等标记荧光检测fluorescence★采用荧光报告基因(GFP、RFP等)或荧光染料进行标记;★需要外接激发光源,利用报告基因、荧光蛋白质或染料产生的荧光,就可以形成体内的生物光源。★荧光染料、蛋白标记能力强;★信号强,成像速度快,操作简便,实验成本较低;★未来可用于人;★适用范围广,可以是动物、细胞、微生物,也可以是抗体、药物、纳米材料等。★存在自发荧光,影响灵敏度;★光容易被动物组织吸收;★检测深度受限;★背景光干扰,定量准确度低
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2.NaHCO3,Ba(OH)3,H2SO4
3.HCL,NaAlO2,NaHSO4
4.Ca(OH)2,Na2CO3,BaCO3
谢谢了
要原因
C.MgCl2溶液和氨水D.盐酸和NaAlO2溶液
为什么
2.NaNO3FeCl3AgNO3
分别有什么现象?谢谢回答!
(1)优级纯试剂 亦称保证试剂,为一级品,纯度高,杂质极少,主要用于精密分析和科学研究,常以GR表示。
(2)分析纯试剂 亦称分析试剂,为二级品,纯度略低于优级纯,杂质含量略高于优级纯,适用于重要分析和一般性研究工作,常以AR表示。
(3)化学纯试剂 为三级品,纯度较分析纯差,但高于实验试剂,适用于工厂、学校一般性的分析工作,常以CP表示。
(4)实验试剂 为四级品,纯度比化学纯差,但比工业品纯度高,主要用于一般化学实验,不能用于分析工作,常以 LR表示。
以上按试剂纯度的分类法已在我国通用。根据化学工业部颁布的“化学试剂包装及标志”的规定,化学试剂的不同等级分别用各种不同的颜色来标志,见表1。
表1 我国化学试剂的等级及标志
暂无品牌问答