尿素Urea

• 产品编号：04821530      品牌：MP       原厂货号：04821530
• 产品分类：生化试剂 > 生化试剂 > 常用化学试剂
• 应用分类：蛋白质研究 > 蛋白-蛋白相互作用
  　　　　　行业及应用 > 农业生物技术

描述：

Description: Urea is the principal end product of nitrogen metabolism in most mammals, formed by the enzymatic reactions of the Kreb's cycle.

Urea is a mild agent usually used in the solubilization and denaturation of proteins.^4,8,12,16 It is also useful for renaturing proteins from samples already denatured with 6 M guanidine hydrochloride such as inclusion bodies^9,17; and in the extraction of the mitochondrial complex.²⁰ It is commonly used to solubilize and denature proteins for denaturing isoelectric focusing and two-dimensional electrophoresis^2,4,5,10,16 and in acetic acid-urea PAGE gels.¹⁸ Preparing samples for two-dimensional polyacrylamide electrophoresis (2D-PAGE) involves solubilization, denaturation and reduction in order to completely disrupt the interactions between the proteins.¹⁶ Due to the diversity of samples which are analyzed by 2D gel electrophoresis, there is no single method of sample preparation that works in all cases. Ideally, all non-covalently bound protein complexes and aggregates should be denatured to form a solution of individual polypeptides.⁴ However, regardless of the method used, protein modifications which might result in artifactual spots on 2D maps must be minimized. For example, samples containing urea must not be heated as this may introduce considerable charge heterogeneity due to carbamylation of the proteins. Samples should be kept cold at all times and handling should be kept to a minimum.²¹

Urea in solution is in equilibrium with ammonium cyanate. The form that reacts with protein amino groups is isocyanic acid. Urea in the presence of heat and protein leads to carbamylation of the proteins. Carbamylation by isocyanic acid interferes with protein characterization because isocyanic acid reacts with the amino terminus of proteins, preventing N-terminal sequencing. Isocyanic acid also reacts with side chains of lysine and arginine residues resulting in a protein that is unsuitable for many enzymatic digests. In addition, carbamylation often leads to confusing results from peptides having unexpected retention times and masses.⁶

When performing enzymatic protein digests it is important to remove urea first.²¹ Even though some enzymes will tolerate small amounts of urea, the elevated temperature used for most reactions will lead to carbamylation during the course of the digest. The urea can be removed prior to digest by fast reversed phase chromatography, spin columns, or dialysis.

Urea is used in cell or tissue culture media to increase the osmolality.³

Urea has also been used as fertilizer because of the easy availability of nitrogen; in animal feeds; it is reacted with aldehydes to make resins and plastics; condensed with malonic ester to form barbituric acid; used in the paper industry to soften cellulose; used as a diuretic; enhances the action of sulfonamides; an antiseptic.¹

Typical Use: Urea is typically used at a concentration of 8 M for protein denaturation or solubilization. A final concentration of 5 M urea is commonly used in molecular biology for sequencing gels. To prevent carbamylation, do not heat urea containing buffers above 37°C.

尿素别名碳酰二胺、碳酰胺、脲 。是由碳、氮、氧和氢组成的有机化合物，又称脲(与尿同音)。其化学公式为 CON2H4、CO(NH2)2 或 CN2H4O，国际非专利药品名称为 Carbamide。

尿素用途：
用于分离氮的氧化物和亚硝 酸及色层分析，也用作生物培养剂.用作肥料、动物饲料、炸 药、稳定剂和制脲醛树脂等的原料.尿素是农药生产的重要原料，可以生产杀菌剂霜脲氰、乙嘧酚，杀虫剂三唑磷、伏杀硫磷、嘧啶氧磷、杀螟腈、胺菊酯，除草剂杀草隆等。农业上用作氮肥，工业上用作饲料添加剂，用于制造炸 药、稳定剂和脲醛树脂等.是农作物肥料，用以提高尿素中氮素的利用率.用作肥料,动物饲料,炸 药,稳定剂和制脲醛树脂等原料。

实验室应用：
尿素能非常有效的使蛋白质变性，尤其能非常有效地破坏非共价键结合的蛋白质。这特点可以提高某些蛋白质的可溶性，其浓度可达10摩尔/体积。尿素也可用来制造硝酸尿素。

原厂资料：

注意事项：

Typical procedure for deionizing urea solutions:

1.Dissolve urea in deionized water to the desired concentration.
2.For every 10 ml of solution, add 1 g of Amberlite® IRA-910 (MP # 150323).
3.Stir for one hour at room temperature.

Biuret Reaction:

Water solutions decompose on heating, giving off some NH₃. Pure urea should not give the biuret reaction unless heated above the melting point.¹ Reagent grade urea may give a positive biuret reaction