低密度脂蛋白（LDL）是由极低密度脂蛋白（VLDL）转变而来，主要功能是把胆固醇运输到全身各处细胞，运输到肝脏合成胆酸，其可用于研究受体介导的内吞作用过程，尤其是在动脉粥样硬化等疾病中，其血浆来源的LDL可用于研究LDL在功能和代谢中的氧化作用。
氧化的LDL（Ox-LDL）是修饰LDL中的一类。修饰的LDL除包括氧化修饰的LDL外，还包括乙酰化LDL及丙二醛（MDA）、4-羟烯酸（4-HNE）直接结合的LDL，这些未经氧化修饰而仅经一般化学修饰的LDL称为衍化的LDL。不同于衍化的LDL，Ox-LDL 的生理学独特性表现在：
1）在细胞生理功能影响上，Ox-LDL可诱发细胞毒性作用，影响花生四烯酸的代谢，抑制胆固醇酯化作用等，但衍化的LDL无上述效应；
2）Ox-LDL消耗LDL内源性抗氧化物质，使LDL上的维生素E含量下降，而MDA-LDL无上述效应；
3）氧化修饰涉及脂质过氧化反应，LDL中的PUFAs被氧化。MDA对LDL修饰，是直接和ApoB-100结合成希夫氏碱，脂质过氧化反应轻微；
4）氧化LDL在氧化程度低时，ApoB降解；在氧化程度高时，ApoB又可发生再聚合。MDA对LDL的修饰，ApoB无降解、聚合反应发生；
5）Ox-LDL 产生的荧光峰波长为430 nm，而MDA -LDL的荧光峰波长为460 nm。Ox-LDL不经LDL受体代谢，由清道夫受体识别、结合、内吞饮入细胞并丧失正常的胆固醇代谢途径，引起细胞内脂质沉积，泡沫样变。
LDL氧化修饰的方式有很多种，常见的有：
1）细胞介导的LDL氧化修饰，又称为生物氧化修饰的LDL。如内皮细胞，巨噬细胞，单核细胞都具有此功能；
2）过度金属离子介导的LDL氧化修饰，如Ca²⁺，Fe²⁺等；还有其他形式的氧化修饰，包括物理方法如紫外线，或过氧化物酶催化。
密度：1.019-1.063 g/mL
成分：78–80% 脂质（Lipid）；20–22% 蛋白质（Protein）
蛋白质测定：改良型劳里法（Modified Lowry），以牛血清白蛋白（BSA）为标准品
来源：人血浆
本产品由新鲜非冷冻血浆制备而成。经美国食品药品监督管理局（FDA）要求的检测证实，该血浆乙型肝炎表面抗原（HBsAg）、丙型肝炎抗体（anti-HCV）、乙型肝炎核心抗体（anti-HBc）检测结果均为阴性，1 型和 2 型人类免疫缺陷病毒抗体（anti-HIV 1 & 2）检测结果亦为阴性。
阿拉丁的产品均为实验室试剂，不得用于人体给药或任何药物用途。仅限科研使用。
Low-density lipoprotein (LDL) is derived from very low-density lipoprotein (VLDL). Its main function is to transport cholesterol to cells throughout the body and to the liver for bile acid synthesis. LDL can be used to study the process of receptor-mediated endocytosis, especially in diseases such as atherosclerosis, where plasma-derived LDL can be employed to investigate the oxidative effects of LDL in terms of its function and metabolism.
Oxidized LDL (Ox-LDL) is a type of modified LDL. In addition to oxidatively modified LDL, modified LDL also includes acetylated LDL and LDL directly bound to malondialdehyde (MDA) or 4-hydroxynonenal (4-HNE). Such LDL that undergoes only general chemical modification without oxidative modification is referred to as derived LDL. Unlike derived LDL, the physiological uniqueness of Ox-LDL is manifested in the following aspects:
1) In terms of the impact on cellular physiological functions, Ox-LDL can induce cytotoxicity, affect the metabolism of arachidonic acid, and inhibit cholesterol esterification, while derived LDL does not exhibit these effects;
2) Ox-LDL consumes endogenous antioxidants in LDL, leading to a decrease in the vitamin E content in LDL, which is not observed in MDA-LDL;
3) Oxidative modification involves lipid peroxidation reactions, in which polyunsaturated fatty acids (PUFAs) in LDL are oxidized. The modification of LDL by MDA occurs through the direct formation of Schiff bases with ApoB-100, accompanied by a slight lipid peroxidation reaction;
4) When the oxidation degree of Ox-LDL is low, ApoB is degraded; when the oxidation degree is high, ApoB can undergo repolymerization. In contrast, the modification of LDL by MDA does not cause the degradation or polymerization of ApoB;
5) The fluorescence peak wavelength of Ox-LDL is 430 nm, while that of MDA-LDL is 460 nm. Ox-LDL is not metabolized via LDL receptors; instead, it is recognized, bound, and endocytosed into cells by scavenger receptors, resulting in the loss of the normal cholesterol metabolism pathway, intracellular lipid deposition, and foam cell formation.
There are various methods for the oxidative modification of LDL, with the common ones listed below:
1) Cell-mediated oxidative modification of LDL, also known as biologically oxidized LDL. For example, endothelial cells, macrophages, and monocytes all possess this function;
2) LDL oxidative modification mediated by transition metal ions, such as Ca²⁺ and Fe²⁺; Additionally, there are other forms of oxidative modification, including physical methods like ultraviolet radiation, or catalysis by peroxidase.
Density: 1.019-1.063 g/mL
Composition: 78 – 80% Lipid; 20 – 22%
Protein Protein Determination: Modified Lowry based on BSA as standard
Source: Human Plasma
Prepared from fresh, non-frozen plasma shown to be non reactive for HBsAg, anti-HCV, anti-HBc, and negative for anti-HIV 1 & 2 by FDA-required tests.
Aladdin products are laboratory reagents and are not to be administered to humans or used for any drug purpose. For research use only.
ZJ26F0838366
危险品化学品经营许可证（带存储）