Identification and quantification of major Maillard cross-links in human serum albumin and lens protein - Evidence for glucosepane as the dominant compound
Identification and quantification of major Maillard cross-links in human serum albumin and lens protein - Evidence for glucosepane as the dominant compound
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DOI：
10.1074/jbc.m202681200
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发表时间：
2002-07-12
影响因子：
4.8
通讯作者：
Lederer, MO
中科院分区：
文献类型：
--
作者：
Biemel, KM;Friedl, DA;Lederer, MO
糖基化反应导致蛋白质修饰（晚期糖基化终产物）导致与一般衰老过程和糖尿病长期并发症相关的各种病理。然而，到目前为止，在体内检测到的相关化合物很少。我们现在报告了在人体材料中首次明确鉴定赖氨酸-精氨酸交联葡萄糖5、DOGDIC 6、MODIC 7和GODIC 8。为了通过液相色谱-电喷雾电离质谱联用准确定量，c -13标记的参比化合物被独立合成。化合物5-8分别由a-二羰基化合物N-6-（2,3-二羟基-5,6-二氧己基）- l -赖氨酸（1a,b）、3-脱氧葡萄糖酮(2)、甲基乙二醛(3)和乙二醛(4)形成。蛋白质结合的二脱氧蛋白la，b似乎对交联具有重要意义，因为它可能不像2-4那样容易被哺乳动物酶解毒。因此，后续产物葡糖苷5被发现是优势化合物。糖尿病人血清白蛋白中5/mg蛋白含量高达42.3 pmol；5的水平与糖化血红蛋白HbA（1c）显著相关。在正常血糖的晶状体蛋白的水不溶性部分中，5的浓度在132.3 - 241.7 pmol/mg之间。晚期糖氧化终产物GODIC 8在褐变透镜中显著升高，表明该材料的氧化应激增强。因此，化合物5-8似乎注定是病理生理过程的标记物。
Glycation reactions leading to protein modifications (advanced glycation end products) contribute to various pathologies associated with the general aging process and long term complications of diabetes. However, only few relevant compounds have so far been detected in vivo. We now report on the first unequivocal identification of the lysine-arginine cross-links glucosepane 5, DOGDIC 6, MODIC 7, and GODIC 8 in human material. For their accurate quantification by coupled liquid chromatography-electrospray ionization mass spectrometry, C-13-labeled reference compounds were synthesized independently. Compounds 5-8 are formed via the a-dicarbonyl compounds N-6-(2,3-dihydroxy-5,6-dioxohexyl)-L-lysinate (1a,b), 3-deoxyglucosone (2), methylglyoxal (3), and glyoxal (4), respectively. The protein-bound dideoxyosone la,b seems to be of prime significance for cross-linking because it presumably is not detoxified by mammalian enzymes as readily as 2-4. Hence, the follow-up product glucosepane 5 was found to be the dominant compound. Up to 42.3 pmol of 5/mg of protein was identified in human serum albumin of diabetics; the level of 5 correlates markedly with the glycated hemoglobin HbA(1c). In the water-insoluble fraction of lens proteins from normoglycemics, concentration of 5 ranges between 132.3 and 241.7 pmol/mg. The advanced glycoxidation end product GODIC 8 is elevated significantly in brunescent lenses, indicating enhanced oxidative stress in this material. Compounds 5-8 thus appear predestined as markers for pathophysiological processes.