Novel HPPD Inhibitor Screeing And The Study Of The Biological Activity Of Pyrabactin Derivatives

p-Hydroxyphenylpyruvate Dioxygenase(HPPD),except a few of the bacteria,which can be widely found in most of the aerobic organism.HPPD involved in the process of catabolism of tyrosine and phenylalance,it can catalyzes oxygenation of 4-hydroxyyphenylpyruvate acid(HPPA)to generate homogentisate acid(HGA).Studies show that HPPD is an important target enzyme,with the significance research of medicine and agronomy.Human HPPD enzyme associated with hereditary tyrosine hematic disease,it is a kind of autosomal recessive genetic disease.In plants,HPPD is an albino type herbino type herbicide target enzyme,the biosynthesis of plastoquinones and tocopherols will be prevented once HPPD is inhibited,which leads to the decrease the formation of carotenoids,blocking of photosynthetic electron transfer chain and photooxidation of chloroplasts,cause plant albio symptoms to death.Based on HPPD plays an important role in medicine and agriculture,we choose human HPPD and Arabidopsis thaliana HPPD(hHPPD and AtHPPD)as the research object.We expect to select high inhibitory of new HPPD inhibitors activity on enzyme levels,thus further guidance synthesis and development of new inhibitors.In the thesis,work of this part is mainly including the following three aspects:1.Based on the building of the hHPPD and AtHPPD cloning expression system in our previous research.By excessive expression of hHPPD and AtHPPD in vitro,we established a new enzyme assay-enzyme coupling reaction method.2.Through high-throughput screening of three commercialized HPPD inhibitors and three new types HPPD inhibitors which were designed and synthesized by our group,we studied the inhibitor kinetics of them.3.We summarized the inhibition constant Ki value of the commercialized and three kinds of 322 new HPPD inhibitors,and summarized their structure-activity relationship respectively.In addition,abscisic acid(ABA)is one of the five plant hormones.It plays an important role in physiological processes of the plant growth and drought resistance,and also has a huge development potential in agricultural production.Pyrabactin as the structure and function of ABA analogs,it is easier and more stable than ABA on the synthesis.Therefore,based on the skeleton structure renovation Pyrabactin,we choose to study Pyrabactin and its derivatives on arabidopsis root growth inhibition activity.Work of this part is mainly including the following three aspects:1.The first time we have successfully established on arabidopsis root growth inhibition activity screening of experimental conditions in our group,suitable for the study of the screening system is established.2.We treated Arabidopsis with 100 ?M final concentration.Through testing the root length of Arabidopsis growthing,we screened 71 compounds and then summarized the corresponding inhibition rate.3.We chose 10 highly active compounds of similar structure.Compared with ABA and Pyrabactin,we determined and summarized their half inhibition rate(IC50 value)of arabidopsis root growth inhibition.In summary,this paper established the high-throughput screening system of HPPD inhibitors,screened new HPPD inhibitors and compared with the Ki of value commercializd inhibitors.We summarized three different structure types of structure-activity relationship on the enzyme levels.It provided the theoretical basis and innovative ideas for the design and development of novel HPPD inhibitors.In addition,this paper established the method of biological activity research for Pyrabactin and its derivatives.It was used to guide the design,synthesis of new Pyrabactin derivatives.It played an important rolea on screening and had highly inhibitory active effect on plant root length growth which were new analogues skeleton of ABA function analogs.