Ahmed M U, Brinkmann Frye E, Degenhardt T P, Thorpe S R, Baynes J W
Department of Chemistry and Biochemistry, University of South Carolina, Columbia, SC 29208, USA.
Biochem J. 1997 Jun 1;324 ( Pt 2)(Pt 2):565-70. doi: 10.1042/bj3240565.
Advanced glycation end-products and glycoxidation products, such as Nepsilon-(carboxymethyl)lysine (CML) and pentosidine, accumulate in long-lived tissue proteins with age and are implicated in the aging of tissue proteins and in the development of pathology in diabetes, atherosclerosis and other diseases. In this paper we describe a new advanced glycation end-product, Nepsilon-(carboxyethyl)lysine (CEL), which is formed during the reaction of methylglyoxal with lysine residues in model compounds and in the proteins RNase and collagen. CEL was also detected in human lens proteins at a concentration similar to that of CML, and increased with age in parallel with the concentration of CML. Although CEL was formed in highest yields during the reaction of methylglyoxal and triose phosphates with lysine and protein, it was also formed in reactions of pentoses, ascorbate and other sugars with lysine and RNase. We propose that levels of CML and CEL and their ratio to one another in tissue proteins and in urine will provide an index of glyoxal and methylglyoxal concentrations in tissues, alterations in glutathione homoeostasis and dicarbonyl metabolism in disease, and sources of advanced glycation end-products in tissue proteins in aging and disease.
晚期糖基化终产物和糖氧化产物，如Nε-（羧甲基）赖氨酸（CML）和戊糖苷，会随着年龄的增长在长寿组织蛋白中积累，并与组织蛋白的老化以及糖尿病、动脉粥样硬化和其他疾病的病理发展有关。在本文中，我们描述了一种新的晚期糖基化终产物，Nε-（羧乙基）赖氨酸（CEL），它在甲基乙二醛与模型化合物以及蛋白质核糖核酸酶和胶原蛋白中的赖氨酸残基反应过程中形成。在人晶状体蛋白中也检测到了CEL，其浓度与CML相似，并且随着年龄的增长与CML的浓度平行增加。尽管在甲基乙二醛和磷酸丙糖与赖氨酸和蛋白质的反应中CEL的生成量最高，但在戊糖、抗坏血酸和其他糖类与赖氨酸和核糖核酸酶的反应中也会形成CEL。我们认为，组织蛋白和尿液中CML和CEL的水平及其相互比例将提供组织中乙二醛和甲基乙二醛浓度的指标、疾病中谷胱甘肽稳态和二羰基代谢的改变，以及衰老和疾病中组织蛋白晚期糖基化终产物的来源。
