Methanol, an aliphatic alcohol widely used in the industry, causes acute and chronic intoxications associated with severe long-term health damage, including permanent visual impairment, brain damage, mainly necrosis of the basal ganglia and high mortality due to cancer. However, the role of formaldehyde, an intermediate metabolite of methanol oxidation, in methanol toxicity remains unclear. Thus, we studied the reactivity of several amino acids and peptides in the presence of formaldehyde by identifying products by direct infusion electrospray high-resolution mass spectrometry (MS) and matrix-assisted laser desorption-ionization MS. Cysteine, homocysteine and two peptides, CG and CGAG, provided cyclic products with a +12 amu mass shift with respect to the original compounds. The proposed structures of the products were confirmed by high-resolution tandem MS. Moreover, the formation of the products with +12 amu mass shift was also shown for two biologically relevant peptides, fragments of ipilimumab, which is a human IgG1 monoclonal antibody against cytotoxic T-lymphocyte-associated protein 4. Overall, our experimental results indicate that formaldehyde reacts with some amino acids and peptides, yielding covalently modified structures. Such chemical modifications may induce undesirable changes in the properties and function of vital biomolecules (e.g., hormones, enzymes) and consequently pathogenesis.

中文翻译：

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甲醛与氨基酸和多肽反应，可能在急性甲醇中毒中起作用。

甲醇是一种在行业中广泛使用的脂肪醇，会引起急性和慢性中毒，与严重的长期健康损害相关，包括永久性视力损害，脑部损害（主要是基底神经节坏死）和癌症导致的高死亡率。但是，甲醛（甲醇氧化的中间产物）在甲醇毒性中的作用仍不清楚。因此，我们通过直接输注电喷雾高分辨率质谱（MS）和基质辅助激光解吸电离MS鉴定产物，研究了甲醛存在下几种氨基酸和肽的反应性。半胱氨酸，高半胱氨酸和两种肽CG和CGAG提供的环状产物的质量相对于原始化合物为+12 amu。所提出的产品结构已通过高分辨率串联质谱确证。此外，还显示了两种生物学上相关的肽，即ipilimumab的片段，其质量位移为+12 amu，该产物是针对细胞毒性T淋巴细胞相关蛋白4的人IgG1单克隆抗体。总的来说，我们的实验结果表明，甲醛与某些氨基酸和肽反应，产生共价修饰的结构。此类化学修饰可能会导致重要生物分子（例如激素，酶）的性质和功能发生不良变化，从而导致发病机理。它是一种针对细胞毒性T淋巴细胞相关蛋白4的人IgG1单克隆抗体。总的来说，我们的实验结果表明甲醛与某些氨基酸和多肽反应，产生共价修饰的结构。此类化学修饰可能会导致重要生物分子（例如激素，酶）的性质和功能发生不良变化，从而导致发病机理。它是一种针对细胞毒性T淋巴细胞相关蛋白4的人IgG1单克隆抗体。总的来说，我们的实验结果表明甲醛与某些氨基酸和多肽反应，产生共价修饰的结构。此类化学修饰可能会导致重要生物分子（例如激素，酶）的性质和功能发生不良变化，从而导致发病机理。