N-acetyl-L-neuraminic acid

• 分子结构分类: 有机化合物 - 有机氧化合物
• 英文名称: N-acetyl-L-neuraminic acid
• 英文别名: (2R,4R,5S,6S)-5-acetamido-2,4-dihydroxy-6-[(1S,2S)-1,2,3-trihydroxypropyl]oxane-2-carboxylic acid
• 化学式: C₁₁H₁₉NO₉
• 分子量: 309.273
• InChiKey: SQVRNKJHWKZAKO-MPXQLOKASA-N

计算性质

• 辛醇/水分配系数(LogP)：
  -3.5
• 重原子数：
  21
• 可旋转键数：
  5
• 环数：
  1.0
• sp3杂化的碳原子比例：
  0.82
• 拓扑面积：
  177
• 氢给体数：
  7
• 氢受体数：
  9

反应信息

• 作为产物：
  描述：

  N-[(3S,4S,5R,6S)-4,5,6,7-tetrahydroxyhept-1-en-3-yl]acetamide 在 甲酸 、 水 、 sodium methylate 作用下， 以 1,4-二氧六环 、 甲醇 为溶剂， 反应 360.0h， 生成 N-acetyl-L-neuraminic acid
  参考文献：
  名称：

  唾液酸及其衍生物的三步合成。

  摘要：

  DOI：

  10.1002/anie.200601555

文献信息

• Directed evolution of N-acetylneuraminic acid aldolase to catalyze enantiomeric aldol reactions
  作者：Masaru Wada、Che-Chang Hsu、Dirk Franke、Michael Mitchell、Andreas Heine、Ian Wilson、Chi-Huey Wong

  DOI：10.1016/s0968-0896(03)00052-x

  日期：2003.5

  inversion of enantioselectivity toward KDO and the second generation variant contains an additional amino acid change Val251Ile outside the alpha,beta-barrel active site that improves the enantiomeric formation of L-sialic acid and L-KDO. The X-ray structure of the triple mutant epNanA.2.5 at 2.3A resolution showed no significant difference between the wild-type and the mutant enzymes. We probed the potential

  扩大底物特异性和立体选择性的范围是目前酶催化中的关注点。使用易于出错的PCR进行体外定向进化，已改变了大肠杆菌的Neu5Ac醛缩酶，以提高其对对映体底物（包括N-乙酰基-L-甘露糖胺和L-阿拉伯糖）的催化活性，从而产生L-唾液酸和L-KDO ，是相应的天然D糖的镜像糖。第一代变异体在（alpha，beta）（8）桶活性位点以外包含两个突变（Tyr98His和Phe115Leu），表现出对KDO的对映选择性反转，第二代变异体在alpha，beta外部包含一个额外的氨基酸变化Val251Ile -桶状活性位点，可改善L-唾液酸和L-KDO的对映体形成。在2.3A分辨率下，三重突变epNanA.2.5的X射线结构显示野生型和突变酶之间无显着差异。我们在Val251（最靠近席夫碱形成Lys165的突变残基）处的饱和诱变下，探索了对映选择性的潜在结构“热点”。所选变体通过替换为另一个疏水残基亮氨酸而
• Unusual stereoselectivity in sialic acid aldolase-catalyzed aldol condensations: synthesis of both enantiomers of high-carbon monosaccharides
  作者：Chun Hung Lin、Takeshi Sugai、Randall L. Halcomb、Yoshitaka Ichikawa、Chi Huey Wong

  DOI：10.1021/ja00052a008

  日期：1992.12

  An inversion of stereoselectivity in aldol condensations catalyzed by sialic acid aldolase (from Escherichia coli, Shinko American Inc.) was observed when L-mannose, 6-deoxy-L-mannose, L-talose, 2-deoxy-L-glucose, 2-deoxy-L-rhamnose, N-acetyl-L-mannosamine, D-gulose, D-arabinose, and 2-azido-2-deoxy-L-mannose were used as acceptor substrates. In all substrates tested, except the last three, a complete inversion of stereoselectivity was observed; i.e., the C-nucleophile of pyruvate attacks the re face of the acceptor carbonyl instead of the si face as in the normal case for the enantiomeric substrates. Examination of the product distribution during the course of enzymatic reactions indicates that the stereoselectivity is thermodynamically controlled in nature; i.e., attack on the re face would take place if the resulting product would be more stable than the one from the si face attack. Both enantiomers of several high-carbon monosaccharides are now accessible via the aldolase reactions. A new practical procedure has also been developed for the preparation of the aldolase products where unreacted pyruvate (usually used in 7-fold excess to drive the reaction) is decomposed with pyruvate decarboxylase to simplify product isolation.
• Three-Step Synthesis of Sialic Acids and Derivatives
  作者：Zhangyong Hong、Lei Liu、Che-Chang Hsu、Chi-Huey Wong

  DOI：10.1002/anie.200601555

  日期：2006.11.13