Kamerling J P, Schauer R, Shukla A K, Stoll S, Van Halbeek H, Vliegenthart J F
Eur J Biochem. 1987 Feb 2;162(3):601-7. doi: 10.1111/j.1432-1033.1987.tb10681.x.
Highly purified N-acetyl-4-O-acetylneuraminic acid (Neu4,5Ac2), N-acetyl-7-O-acetylneuraminic acid (Neu5,7Ac2) and N-acetyl-7,9-di-O-acetylneuraminic acid (Neu5,7,9Ac3) were used to study spontaneous migrations of acetyl groups between hydroxyl groups. The techniques applied involved thin-layer chromatography, gas-liquid chromatography/mass spectrometry, high-performance liquid chromatography and 360-MHz 1H-NMR spectroscopy. It was found that at pH values at which no significant de-O-acetylation is observed: (a) Neu5,7Ac2 can easily be transformed into Neu5,9Ac2, (b) Neu5,7,9Ac3 yields an equilibrium of Neu5,7,9Ac3 and Neu5,8,9Ac3 in a molar ratio of approximately 1:1, and (c) Neu4,5Ac2 does not give rise to O-acetyl migrations. The importance of these findings is discussed in terms of the biosynthesis of O-acetylated sialic acids.
使用高度纯化的N-乙酰基-4-O-乙酰神经氨酸（Neu4,5Ac2）、N-乙酰基-7-O-乙酰神经氨酸（Neu5,7Ac2）和N-乙酰基-7,9-二-O-乙酰神经氨酸（Neu5,7,9Ac3）来研究乙酰基在羟基之间的自发迁移。所应用的技术包括薄层色谱法、气-液色谱/质谱法、高效液相色谱法和360兆赫的1H-NMR光谱法。发现在未观察到明显脱O-乙酰化的pH值下：（a）Neu5,7Ac2可轻易转化为Neu5,9Ac2，（b）Neu5,7,9Ac3产生摩尔比约为1:1的Neu5,7,9Ac3和Neu5,8,9Ac3的平衡，并且（c）Neu4,5Ac2不会引起O-乙酰基迁移。从O-乙酰化唾液酸的生物合成角度讨论了这些发现的重要性。
