Core Unit Proteomics, Institute of Toxicology, Hannover Medical School, Carl-Neuberg-Straße 1, 30625 Hannover, Germany.
J Proteome Res. 2023 Jun 2;22(6):2141-2143. doi: 10.1021/acs.jproteome.2c00764. Epub 2023 Apr 4.
Lysine residues in proteins undergo multiple enzymatic and nonenzymatic post-translational modifications (PTMs). The terminal ε amine group of lysine residues in proteins is carbonylated chemically by carbonyl species such as glyoxal (GO; OCH-CHO, CHO; MW 58) and methylglyoxal (MGO; OCH-C(=O)-CH, CHO; MW 72) that are derived from the metabolism of endogenous substances including glucose. The dicarbonyl species malondialdehyde (MDA, OCH-CH-CHO, CHO; MW 72) is generated by enzymatic and nonenzymatic peroxidation of polyunsaturated fatty acids (PUFAs). GO, MGO, and MDA occur in biological systems in their free forms and in their conjugated forms adducted to free amino acids and amino acid residues in proteins, notably to lysine. MDA is a C-H-acidic acid (p, 4.45). Biological MDA is widely used as a biomarker of lipid peroxidation. The most frequently analyzed biological samples for MDA are plasma and serum. Reportedly, MDA concentrations in plasma and serum samples of healthy and ill humans range by several orders of magnitude. The most severe preanalytical contributor is artificial formation of MDA in lipid-rich samples such as plasma and serum. In very few publications, plasma MDA concentrations were reported to lie in the lower mM-range.
蛋白质中的赖氨酸残基经历多种酶促和非酶促的翻译后修饰（PTMs）。蛋白质中赖氨酸残基的末端ε氨基基团被羰基物质如乙二醛（GO；OCH-CHO，CHO；MW 58）和甲基乙二醛（MGO；OCH-C(=O)-CH，CHO；MW 72）化学羰基化，这些羰基物质来源于包括葡萄糖在内的内源性物质的代谢。二羰基物质丙二醛（MDA，OCH-CH-CHO，CHO；MW 72）是由多不饱和脂肪酸（PUFAs）的酶促和非酶促过氧化产生的。GO、MGO 和 MDA 以游离形式和与游离氨基酸以及蛋白质中氨基酸残基结合的形式存在于生物系统中，特别是与赖氨酸结合。MDA 是一种 C-H 酸（p，4.45）。生物 MDA 被广泛用作脂质过氧化的生物标志物。最常用于分析 MDA 的生物样本是血浆和血清。据报道，健康和患病人类的血浆和血清样本中的 MDA 浓度相差几个数量级。最严重的预分析贡献者是富含脂质的样本（如血浆和血清）中 MDA 的人工形成。在极少数出版物中，报告了血浆 MDA 浓度处于较低的 mM 范围内。
