Pan Yanbin, Ayani Tiffany, Nadas Janos, Wen Shouming, Guo Zhongwu
Department of Chemistry, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106, USA.
Carbohydr Res. 2004 Aug 23;339(12):2091-100. doi: 10.1016/j.carres.2004.05.028.
N-Acetyl-D-neuraminic acid (NeuNAc) aldolase is an important enzyme for the metabolic engineering of cell-surface NeuNAc using chemically modified D-mannosamines. To explore the optimal substrates for this application, eight N-acyl derivatives of D-mannosamine were prepared, and their accessibility to NeuNAc aldolase was quantitatively investigated. The N-propionyl-, N-butanoyl-, N-iso-butanoyl-, N-pivaloyl-, and N-phenylacetyl-D-mannosamines proved to be as good substrates as, or even better than, the natural N-acetyl-D-mannosamine, while the N-trifluoropropionyl and benzoyl derivatives were poor. It was proposed that the electronic effects might have a significant influence on the enzymatic aldol condensation reaction of D-mannosamine derivatives, with electron-deficient acyl groups having a negative impact. The results suggest that N-propionyl-, N-butanoyl-, N-iso-butanoyl-, and N-phenylacetyl-D-mannosamines may be employed to bioengineer NeuNAc on cells.
N-乙酰-D-神经氨酸(NeuNAc)醛缩酶是利用化学修饰的D-甘露糖胺对细胞表面NeuNAc进行代谢工程改造的一种重要酶。为了探索该应用的最佳底物,制备了8种D-甘露糖胺的N-酰基衍生物,并对它们被NeuNAc醛缩酶作用的情况进行了定量研究。结果表明,N-丙酰基-、N-丁酰基-、N-异丁酰基-、N-新戊酰基-和N-苯乙酰基-D-甘露糖胺是与天然N-乙酰-D-甘露糖胺一样好甚至更好的底物,而N-三氟丙酰基和苯甲酰基衍生物则较差。研究提出,电子效应可能对D-甘露糖胺衍生物的酶促醛醇缩合反应有显著影响,缺电子的酰基具有负面影响。结果表明,N-丙酰基-、N-丁酰基-、N-异丁酰基-和N-苯乙酰基-D-甘露糖胺可用于在细胞上对NeuNAc进行生物工程改造。