1996 Fiscal Year Final Research Report Summary
The appearance of enzyme activity for D-amino acid in highly concentrated ammonium phosphate solution
Project/Area Number |
06680551
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Research Category |
Grant-in-Aid for Scientific Research (C)
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Allocation Type | Single-year Grants |
Section | 一般 |
Research Field |
Bioorganic chemistry
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Research Institution | University of Tsukuba |
Principal Investigator |
SHIMADA Akihiko Univeristy of Tsukuba, Institution of Applied Biochemistry, assistant Professor, 応用生物化学系, 講師 (90235614)
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Project Period (FY) |
1994 – 1996
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Keywords | origin of optical activity / selection mechanism for optical isomers on enzyme / D-tryptophan / tryptophanase / diammoniumhydrogen phosphate |
Research Abstract |
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.
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Research Products
(10 results)