The appearance of enzyme activity for D-amino acid in highly concentrated ammonium phosphate solution

We had elucidated the reaction pathway of tryptophanase-catalysed degradation of D-tryptophan in the presence of diammoniumhydrogen phosphate and had studied selection mechanism of D-amino acids on enzyme for the term of this project。最近从本研究中获得的信息如下：1.金刚石羟基磷酸盐（（NH_4） _2HPO_4）作为活性剂以下50%的饱和度，但作为活性剂以上50%的非竞争性抑制剂。2.反应途径是动力学分析的基础上的饱和度。与D-色氨酸随机绑定Tryptophan和（NH_4） _2HPO_4在快速均衡中。D-色氨酸通过色氨酸酶降解·D-色氨酸· （NH_4） _2HPO_4复合体.3. D-色氨酸与色氨酸酶在（NH_4） _2HPO_4中的缺失结合。增加（NH_4） _2HPO_4改变的抑制类型从竞争性类型通过混合到不竞争性类型的抑制类型.4.结果表明，在活跃位点中绑定位点和催化位点的结果是独立的。在补充中，我建议D-色氨酸的绑定站点独立地为L-色氨酸的行为。5.结果如此之远，在论文中被报道。

We had elucidated the reaction pathway of tryptophanase-catalysed degradation of D-tryptophan in the presence of diammoniumhydrogen phosphate and had studied selection mechanism of D-amino acids on enzyme for the term of this project. Information newly obtained from this research is described below.1.Diammoniumhydrogen phosphate ((NH_4) _2HPO_4) acted on tryptophanase as an activator below 50% saturation, but as a noncompetitive inhibitor above 50% saturation.2.Reaction pathway was satisfactorily clarified on the basis of kinetic analysis. Tryptophanase bound at random with D-tryptophan and (NH_4) _2HPO_4 in rapid equilibrium. D-tryptophan was degraded through tryptophnase・D-tryptophan・ (NH_4) _2HPO_4 complex.3.D-tryptophan bound with tryptophanase in the absence of (NH_4) _2HPO_4. Increasing concentration of (NH_4) _2HPO_4 changed inhibition type from competitive type through mixed type to uncompetitive type.4.The above result indicated that binding site and catalytic site within active site of tryptophanase was independent. In addition, it was suggested that the binding site of D-tryptophan independently behaved for that of L-tryptophan.5.Results so far obtained have been reported in papers.