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

We had elucidated the reaction pathway of tryptophanase-catalysed -tryptophan in thepresence of diammoniumhydrogen phosphate and had studied selection mechanism of D-amino acids onenzyme for the term of this project.信息从这个研究是描述b elow . 1 . diammoniumhydrogen phosphate (nh 4) 2 hpo译文:4)acted on tryptophanase as an activator below50% saturation,but as a noncompetitive inhibitor above 50% saturation.2.Reaction pathway was satisfactorily基础分析。Tryptophanase bound at random with D-tryptophan and（nh_4） _2 hpo_4 in rapid equilibrium. D-tryptophan was degraded through tryptophnase / D-tryptophan（nh_4） _2 hpo_4 complex.3.D-tryptophan bound with tryptophanase in the absence of (nh_4) _2 hpo_4 .Increasing concentration of (nh_4) _2 hpo_4 changed inhibition type from competitive type throughmixed type to uncompetitive type.4.The above result indicated that binding site and catalytic sitewithin active site of tryptophanase was独立。In addition，这是一个suggested that the binding site of D-tryptophan independently behaved for that ofL-tryptophan.5.Results so far obtained been reported in papers。

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.