Research Reactor Institute, Kyoto University, Kumatori, Sennan, Osaka 590-0494, Japan.
J Chromatogr B Analyt Technol Biomed Life Sci. 2011 Nov 1;879(29):3141-7. doi: 10.1016/j.jchromb.2011.05.051. Epub 2011 Jun 12.
Homochirality is essential for life. L-Amino acids are exclusively used as substrates for the polymerization and formation of peptides and proteins in living systems. However, d-amino acids, which are enantiomers of L-amino acids, were recently detected in various living organisms in the form of free D-amino acids and D-amino acid residues in peptides and proteins. In particular, D-aspartyl (Asp) residues have been detected in various proteins from diverse tissues of elderly individuals. Here, we describe three important aspects of our research: (i) a method for detecting D-β-Asp at specific sites in particular proteins, (ii) a likely spontaneous mechanism by which Asp residues in proteins invert and isomerize to the D-β-form with age under physiological conditions, (iii) a discussion of factors that favor such a reaction.
手性是生命的基础。L-氨基酸是生物体内肽和蛋白质聚合及形成的唯一底物。然而，D-氨基酸是 L-氨基酸的对映异构体，最近以游离 D-氨基酸和肽及蛋白质中 D-氨基酸残基的形式在各种生物体中被检测到。特别是，D-天冬氨酸（Asp）残基已在老年人不同组织的各种蛋白质中被检测到。在这里，我们描述了我们研究的三个重要方面：（i）一种用于检测特定蛋白质中特定位置 D-β-Asp 的方法，（ii）在生理条件下，蛋白质中的 Asp 残基随年龄增长自发反转并异构化为 D-β-形式的可能机制，（iii）讨论有利于这种反应的因素。
