Wilker S C, Chellan P, Arnold B M, Nagaraj R H
Center for Vision Research, Department of Ophthalmology, Case Western Reserve University, Cleveland, Ohio, 44106, USA.
Anal Biochem. 2001 Mar;290(2):353-8. doi: 10.1006/abio.2001.4992.
Methylglyoxal (MG), an alpha-dicarbonyl compound, can be produced in vivo by several metabolic pathways and the Maillard reaction. It reacts rapidly with proteins to form advanced glycation end products or AGEs. We previously isolated and characterized a blue fluorescent product of the reaction between MG and arginine, which we named argpyrimidine. We found that argpyrimidine was stable to acid hydrolysis, which allowed us to hydrolyze tissue proteins with 6 N HCl and quantify argpyrimidine by high-performance liquid chromatography. Here we report argpyrimidine concentrations in human lens and serum proteins as determined by HPLC. We have also measured pentosidine, a fluorescent AGE derived from pentose sugars, and compared the concentrations of pentosidine and argpyrimidine. We found two- to threefold higher argpyrimidine concentrations in diabetic serum proteins than in nondiabetic controls (9.3 +/- 6.7 vs 4.4 +/- 3.4 pmol/mg). We found a significant correlation (P = 0.0001) between serum protein argpyrimidine and glycosylated hemoglobin. Argpyrimidine concentrations were approximately seven times greater in brunescent cataractous lenses than in aged noncataractous lenses. Pentosidine concentrations in serum and lens proteins were much lower than argpyrimidine concentrations; in general, argpyrimidine levels were 10--25 times higher than pentosidine. Results from our study confirm that MG-mediated arginine modifications occur in vivo and provide a method for assessing protein-arginine modification by MG in aging and diabetes.
甲基乙二醛（MG）是一种α-二羰基化合物，可通过多种代谢途径和美拉德反应在体内产生。它能迅速与蛋白质反应形成晚期糖基化终产物（AGEs）。我们之前分离并鉴定了MG与精氨酸反应产生的一种蓝色荧光产物，将其命名为精嘧啶。我们发现精嘧啶对酸水解稳定，这使我们能够用6N盐酸水解组织蛋白，并通过高效液相色谱法定量精嘧啶。在此，我们报告通过高效液相色谱法测定的人晶状体和血清蛋白中的精嘧啶浓度。我们还测量了源自戊糖的荧光AGE——戊糖苷，并比较了戊糖苷和精嘧啶的浓度。我们发现糖尿病患者血清蛋白中的精嘧啶浓度比非糖尿病对照组高两到三倍（9.3±6.7对4.4±3.4 pmol/mg）。我们发现血清蛋白精嘧啶与糖化血红蛋白之间存在显著相关性（P = 0.0001）。褐色白内障晶状体中的精嘧啶浓度比老年非白内障晶状体中的大约高七倍。血清和晶状体蛋白中的戊糖苷浓度远低于精嘧啶浓度；一般来说，精嘧啶水平比戊糖苷高10 - 25倍。我们的研究结果证实，MG介导的精氨酸修饰在体内发生，并提供了一种评估MG在衰老和糖尿病中对蛋白质精氨酸修饰的方法。
