Studies On The Enzyme Activity Assay Method, Inducible Expression And Enzymological Properties Of DAHPS

The shikimate pathway(SP), which is biosynthetic pathway of the aromatic amino acid and its the secondary metabolites, is only found in bacteria , fungi and plants, but not in animals. In bacteria and plants, SP is the quite obvious difference, the former mainly synthesizes the aromatic amino acid, the latter not only synthesizes them, but also synthesizes their secondary metabolites, these metabolites is close relative to plant's resistance. DAHPS, the first key enzyme of SP, is playing the vital role in the control chorismate biosynthesis. Its activity directly determines other biosynthesis steps of SP, and is a key factor that affects the aromatic amino acids and their secondary metabolites. Therefore, one enzyme activity assay method which was relatively simple and accurate was sought. The author had researched on DAHPS' enzymological properties, including optimum temperature ,optimum pH, and enzyme activity' change when it were added metal ion, DTT, β-mercaptoethanol, SNP, researched on different material and different disposing way to DAHPS inducible expression difference. These study are helpful to research the functions of SP in the phytosynthesis metabolism and relations between DAHPS and plant's resistance, it is important theory significance and the practical significance regarding crops' resistant research..It was proved that the osazone sulfuric acid development method(OSADM) is a quite ideal DAHPS activity assay method, according to the osazone's absorption map, the linear relations, detecting limit. And OSADM was ensured the third assay enzyme activity method.Four kinds of materials, which are Zhongyou 821,GH01, self compatibility and self incompatibility cabbage, were treated by wound and ultraviolet ray, then the raw enzyme fluid were extracted and the enzyme activity were assayed. The author found that disposed materials' DAHPS activitywere stronger than no disposed, and that different materials were different activities. the raw enzyme fluid of Zhongyou 821 was operated SDS-PAGE, the DAHPS expression obviously increased according to the electrophoretograms after the materials were disposed. It was proved that DAHPS expression was induced, and the different plant had the different resistance to different treatment...