Electron transport system on complex flavoprotein

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Xanthine oxidase and xanthine dehydrogenase are complex metalloflavoproteins that appear to represent alternate forms of the same gene product. The mammalian enzyme exists originally as a dehydrogenase, but it converts to an oxidase during extraction or purification prosedues. The enzyme is formed with two identical subunits, catalyzes the final two step in uric acid metabolism and, in addition, participates also the production of active oxigen species. The molecular weight of subunit is about 150,000, and each contains one molybdopterin, two iron sulfur centers and one FAD.During the catalytic reaction the electrons are transfed between the co-factors. Thus the enzyme contains the electron transport system in itself. Therefor it might be a good model for understanding of electron transfort system in mitochondria and in microsome. One of our gole is to understand the catalytic mechanism and contral mechanism on the enzyme reaction in further detail.Within a given period of time, we mak … More ed up the following studies : 1) analysis of the structure of chickin liver xanthine dehydrogenase which has never been known to convert to an oxidase : [FASEB J.9,995-1003,1995 ; J.Biol.Chem.270,2818-2826,1995], 2) analysis of the mechanism of inhibition by a new inhibitor, sodium-8-(3-methyoxy-4-phenylsulfinylphenyl) pyrazolo [1,5-a]-1,3,5-triazine-4-olate monohydrate, to the catalytic action of milk enzyme : [J.Biol.Chem., 270,7816-7821,1995], 3) analysis of the structure-function relationship of mercaptopyruvate sulfurtransferase which thought to play a role on incorpolation of sulfur into the iron-sulfur protein : [J.Biol.Chem., 270,16230-16235,1995 ; J.Biol.Chem., 271,27395-27401,1996], 4) the expression of wild-type and mutant-type xanthine oxidases in bacurovirus using recombinant DNA technology and the enzymetic analysis and 5) the expression of wild-type and mutant-type superoxide dismutases using recombinant DNA technology and analysis of the structure-function relationship : [Frontiers of reactive oxygen species in biology and medicine, Elsevier Scientific Publishers, B.V., Amusterdam, 135-136,1994]. Less