Thomas Liam A, Emms Vicki L, Vashi Dipti, Fairall Louise, Schwabe John W R, Hopkinson Richard J
Institute for Structural and Chemical Biology and School of Chemistry, University of Leicester, Henry Wellcome Building, Lancaster Road, Leicester, LE1 7RH, UK.
Institute for Structural and Chemical Biology and Department of Molecular and Cell Biology, University of Leicester, Henry Wellcome Building, Lancaster Road, Leicester, LE1 7RH, UK.
Chembiochem. 2025 Jun 16;26(12):e202500138. doi: 10.1002/cbic.202500138. Epub 2025 May 21.
Crotonaldehyde is a human toxin that reacts with nucleophilic groups on DNA and proteins. Putative crotonaldehyde-derived adducts on DNA are reported in cells and patients after ethanol exposure, which implies that crotonaldehyde is formed in cells. Here, we show that proline amide, which is a model of N-terminal proline-containing proteins, catalyzes the aldol condensation of the ethanol metabolite acetaldehyde to crotonaldehyde under physiologically relevant conditions. This reaction is more efficient at neutral pH than under acidic or basic conditions, but is inhibited by competing imidazolidin-4-one formation. Crotonaldehyde formation is also slower than the analogous aldol condensation of propionaldehyde. Comparative studies additionally suggest that proline amide is a more efficient catalyst than other amino acid amides. Overall, the work evidences a biochemically plausible mechanism for intracellular crotonaldehyde formation and implies that proline amide derivatives can catalyze aldol chemistry in humans.
巴豆醛是一种可与DNA和蛋白质上的亲核基团发生反应的人体毒素。据报道，乙醇暴露后，细胞和患者体内的DNA上存在推定的巴豆醛衍生加合物，这表明细胞内会形成巴豆醛。在此，我们表明脯氨酸酰胺（一种含N端脯氨酸的蛋白质模型）在生理相关条件下催化乙醇代谢产物乙醛缩合生成巴豆醛。该反应在中性pH条件下比在酸性或碱性条件下更有效，但会受到竞争性咪唑烷 - 4 - 酮形成的抑制。巴豆醛的形成也比丙醛的类似羟醛缩合反应慢。比较研究还表明，脯氨酸酰胺比其他氨基酸酰胺是更有效的催化剂。总体而言，这项工作证明了细胞内巴豆醛形成的生化合理机制，并表明脯氨酸酰胺衍生物可在人体内催化羟醛化学过程。
