酵母合成的15NL-色氨酸中N元素代谢通量的分析

以葡萄糖为碳源，硫酸铵为氮源，¹⁵N邻氨基苯甲酸为前体物，利用酵母发酵合成¹⁵NL-色氨酸，是合成¹⁵NL-色氨酸的一种新方法。为了有效的利用含氮的化合物，实验过程中，采用¹⁵N标记的邻氨基苯甲酸为示踪剂，分析了N元素在¹⁵NL-色氨酸合成过程中的代谢通量。结果表明，93％外加的邻氨基苯甲酸，被转化为¹⁵NL-色氨酸。硫酸铵在促进菌体生长的同时，0.05％硫酸铵被用于合成邻氨基苯甲酸，并进一步被转化为L-色氨酸，5.95％硫酸铵被直接用于合成¹⁵NL-色氨酸。

Metabolic flux analysis of elemental nitrogen for L-tryptophan biosynthesis in yeast

A new synthesis method for()~(15)N L-tryptophan by yeast fermentation using glucose as carbon source,ammonium sulphate as nitrogen source,and()~(15)N anthranilic acid as a precursor is described.In order to ensure efficient use of the nitrogen source compounds,the metabolic flux of elemental nitrogen was analyzed for L-tryptophan biosynthesis using the()~(15)N anthranilic acid as a tracer in the experimental process.The results indicated that 93% of the L-tryptophan was derived from exogenous anthranilic acid.Ammonium sulphate contributed to the growth of the yeast and anthranilic acid was also synthesized from ammonium sulphate and subsequently converted into L-tryptophan(0.05% of the total yield).A further 5.95% of L-tryptophan was directly synthesized from ammonium sulphate.