ENZYMES IN CARBOHYDRATE SYNTHESIS - N-ACETYLNEURAMINIC ACID ALDOLASE CATALYZED-REACTIONS AND PREPARATION OF N-ACETYL-2-DEOXY-D-NEURAMINIC ACID-DERIVATIVES
ENZYMES IN CARBOHYDRATE SYNTHESIS - N-ACETYLNEURAMINIC ACID ALDOLASE CATALYZED-REACTIONS AND PREPARATION OF N-ACETYL-2-DEOXY-D-NEURAMINIC ACID-DERIVATIVES
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DOI：
10.1021/ja00227a031
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发表时间：
1988-09-14
影响因子：
15
通讯作者：
WONG, CH
中科院分区：
文献类型：
--
作者：
KIM, MJ;HENNEN, WJ;WONG, CH
本文介绍了N-乙酰神经氨酸(Neu5Ac)醛缩酶(E.C.4.1.3.3)底物的结构特征，稳定性研究结果，它在合成Neu5Ac和9-O-乙酰基-Neu5Ac(Neu5，9Ac2)中的应用，以及Neu5Ac向2-脱氧衍生物的化学转化。测定了N-乙酰-D-甘露糖胺(ManNAc)和丙酮酸在pH 7.5和25℃下的动力学参数(Km和Vmax)。C在冷凝方向。利用ManNAc、过量丙酮酸和全固定化Neu5Ac缩醛酶进行30.sbd.50 mmol规模的合成，可获得多克量的Neu5Ac(在溶液中的得率为87-91%，在分离产物中的得率为67%)，而没有显著的酶活性损失。用两种不同的酶反应合成了Neu5，9Ac2，总收率为59%。两种反应分别是在N酶催化下，6-O-乙酰基-甘露醇与丙酮酸缩合。为了说明Neu5Ac作为合成起始原料的用途，我们制备了一种潜在的Neu5Ac相关酶的抑制剂。以Neu5Ac为原料，经三步反应制得甲基4，7，8，9-tetra-O-acetyl-N-acetyl-2-deoxy-.alpha.-neuraminic酸(2-脱氧-α-Neu4，5，7，8，9Ac5OMe)，总收率50%。用~1H、~(13)C核磁共振谱和X-射线单晶衍射法对其结构进行了分析。
This paper describes the structural characteristics of substrates accepted by N-acetylneuraminic acid (Neu5Ac) aldolase (E.C. 4.1.3.3), the results from its stability studies, its use in the synthesis of Neu5Ac and 9-O-acetyl-Neu5Ac(Neu5,9Ac2), and the chemical conversion of Neu5Ac to the 2-deoxy derivatives. Values of kinetic parameters (Km and Vmax) for 14 aldoses including N-acetyl-D-mannosamine (ManNAc) and pyruvate were determined at pH 7.5 and 25.degree. C in the direction of condensation. The 30.sbd.50-mmol-scale synthesis using ManNAc, excess pyruvate, and PAN-immobilized Neu5Ac aldolase provided multigram quantities of Neu5Ac (yield, 87-91% in solution and 67% in isolated products) without a significant loss of enzyme activity. The synthesis using two separate enzyme reactions, acetylation of ManNAc to 6-O-acetylManNAc to 6-O-acetylManNAc catalyzed by protease N and condensation of 6-O-acetyl-ManNAc with pyruvate catalyzed by Neu5Ac aldolase, provided Neu5,9Ac2 in 59% overall yield. To illustrate the utility of Neu5Ac as a synthetic starting material, a potential inhibitor of Neu5Ac-associated enzymes was prepared. Three chemical steps from Neu5Ac provided methyl 4,7,8,9-tetra-O-acetyl-N-acetyl-2-deoxy-.alpha.-neuraminic acid (2-deoxy-.alpha.-Neu4,5,7,8,9Ac5OMe) in 50% overall yield. Its structure was analyzed by 1H and 13C NMR spectroscopy and X-ray crystallography.