1.Novel Method For Determination Of Protein Tyrosine Nitration2.Synthesis And Biological Evaluation Of6-Dehydrogingerdione Analogues

This thesis consists of two projects:One is the development of novel method in determination of protein tyrosine nitration, and the other is the synthesis and biological evaluation of6-dehydrogingerdione analogues.The formation of3-nitrotyrosine in proteins (protein tyrosine nitration), a common posttranslational modification, usually occurs with the excess production of reactive oxygen/nitrogen species, and is found under many pathological conditions from acute to chronic diseases. In the first part of the dissertation, we proposed a novel method in determining the nitration of a protein of interest from complicated biological samples. The key strategy in the approach includes the reduction of nitrotyrosine to aminotyrosine, followed by coupling with the immobilized2-naphthol via diazotization reaction. The captured proteins was subsequently released by breaking the-N=N-double bond via addition of sodium hydrosulfite. The released protein mixture was separated by SDS gel electrophoresis, and the protein of interest could be identified by Western blotting with a specific antibody.In the second part, we synthesized6-dehydrogingerdione and its analogues, and investigated their cytotoxicity against a panel of cancer cell lines. Some of the compounds displayed moderate cytotoxicity with IC50values around30μM. Preliminary mechanism study indicates that the thioredoxin reductase is not involved in the biological activity of those molecules.