Department of Forensic Medicine , Aarhus University , Aarhus 8200 , Denmark.
Department of Chemistry , Aarhus University , Aarhus 8000 , Denmark.
ACS Chem Biol. 2018 Dec 21;13(12):3294-3305. doi: 10.1021/acschembio.8b00732. Epub 2018 Dec 3.
Methylglyoxal (MG) is quantitatively the most important precursor to advanced glycation end-products (AGEs), and evidence is accumulating that it is also a causally linked to diabetes and aging related diseases. Living systems primarily reside on the glyoxalase system to detoxify MG into benign d-lactate. The flux to either glycation or detoxification, accordingly, is a key parameter for how well a system handles the ubiquitous glyoxal burden. Furthermore, insight into proteins and in particular their individual modification sites are central to understanding the involvement of MG and AGE in diabetes and aging related diseases. Here, we present a simple method to simultaneously monitor the flux of MG both to d-lactate and to protein AGE formation in a biological sample by employing an alkyne-labeled methylglyoxal probe. We apply the method to blood and plasma to demonstrate the impact of blood cell glyoxalase activity on plasma protein AGE formation. We move on to isolate proteins modified by the MG probe and accordingly can present the first general inventory of more than 100 proteins and 300 binding sites of the methylglyoxal probe on plasma as well as erythrocytic proteins. Some of the data could be validated against a number of in vivo and in vitro targets for advanced glycation previously known from the literature; the majority of proteins and specific sites however were previously unknown and may guide future research into MG and AGE to elucidate how these are functionally linked to diabetic disease and aging.
甲基乙二醛（MG）是定量上最重要的高级糖基化终产物（AGEs）前体，越来越多的证据表明，它也与糖尿病和衰老相关疾病有关。生命系统主要依靠糖氧还蛋白系统将 MG 解毒为良性的 d-乳酸。因此，无论是糖化还是解毒的通量，都是一个系统处理普遍存在的 MG 负担的关键参数。此外，深入了解蛋白质，尤其是其单个修饰位点，对于理解 MG 和 AGE 在糖尿病和衰老相关疾病中的作用至关重要。在这里，我们提出了一种简单的方法，通过使用炔基标记的甲基乙二醛探针，同时监测生物样品中 MG 向 d-乳酸和蛋白质 AGE 形成的通量。我们将该方法应用于血液和血浆，以证明血细胞糖氧还酶活性对血浆蛋白 AGE 形成的影响。我们继续分离被 MG 探针修饰的蛋白质，并相应地展示了第一个关于血浆以及红细胞蛋白质中超过 100 种蛋白质和 300 个甲基乙二醛探针结合位点的综合清单。一些数据可以与文献中先前已知的许多体内和体外的高级糖基化靶标进行验证；然而，大多数蛋白质和特定的位点以前是未知的，可能会指导未来对 MG 和 AGE 的研究，以阐明它们如何与糖尿病和衰老相关疾病在功能上相关。
