Lee K W, Simpson G, Ortwerth B
Mason Eye Institute, University of Missouri, School of Medicine, Columbia 65212, USA.
Biochim Biophys Acta. 1999 Jan 6;1453(1):141-51. doi: 10.1016/s0925-4439(98)00097-0.
To systematically evaluate the modification of lens proteins by aldose and dicarbonyl sugars during the glycation process, the sugar-dependent incorporation of Lys and Arg, SDS-PAGE profile, amino acid analysis, and fluorophore formation (excitation 370 nm/emission 440 nm) were determined. Reaction mixtures with glycolaldehyde, glyceraldehyde, threose and 3-deoxythreosone showed the greatest extent of Lys crosslinking and fluorescence formation. An increase in fluorescence intensity, but a decrease in Lys and Arg crosslinking, was found with glyoxal, methylglyoxal, hydroxypyruvaldehyde and threosone. In addition glyoxal, methylglyoxal and hydroxypyruvaldehyde caused the specific loss of Arg residues in lens proteins. Reaction mixtures with xylose, xylosone, glucose, glucosone and 3-deoxyglucosone exhibited the least protein modifications; however, incubation with 3-deoxyxylosone resulted in extensive loss of Lys and Arg residues, a higher extent of Lys or Arg crosslinking and significant fluorophore formation. Each sugar exhibited unique characteristics in the modification of lens proteins by glycation. To validly compare the protein modifications occurring during glycation reactions, a systematic approach was employed to evaluate the potential role of aldose and dicarbonyl sugars in protein modification.
为了系统地评估在糖基化过程中醛糖和二羰基糖对晶状体蛋白的修饰作用，测定了赖氨酸（Lys）和精氨酸（Arg）的糖依赖性掺入、十二烷基硫酸钠 - 聚丙烯酰胺凝胶电泳（SDS - PAGE）图谱、氨基酸分析以及荧光团形成（激发波长370 nm/发射波长440 nm）。与乙醇醛、甘油醛、苏糖和3 - 脱氧苏糖的反应混合物显示出最大程度的赖氨酸交联和荧光形成。发现乙二醛、甲基乙二醛、羟基丙酮醛和苏酮糖会使荧光强度增加，但赖氨酸和精氨酸交联减少。此外，乙二醛、甲基乙二醛和羟基丙酮醛会导致晶状体蛋白中精氨酸残基的特异性丢失。与木糖（xylose）、木酮糖（xylosone）、葡萄糖、葡糖酮和3 - 脱氧葡糖酮的反应混合物表现出最少的蛋白质修饰；然而，与3 - 脱氧木酮糖孵育会导致赖氨酸和精氨酸残基大量丢失、赖氨酸或精氨酸交联程度更高以及显著荧光团形成。每种糖在通过糖基化修饰晶状体蛋白方面都表现出独特的特性。为了有效比较糖基化反应过程中发生的蛋白质修饰，采用了一种系统方法来评估醛糖和二羰基糖在蛋白质修饰中的潜在作用。
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