User:Sarah Abdalla/Thioredoxin Reductase: Difference between revisions

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			'''Function and Mechanism'''

	~~<applet load='1h6v' size='300' frame='true' align='right' caption='Insert caption here' />~~		High molecular weight TRs catalyze the reduction of the redox active disulfide of thioredoxin, the enzyme’s cognate substrate. Together with thioredoxin and NADPH, TR forms the thioredoxin system which plays a major role in maintaining a reducing environment within cells. Studies on thioredoxin have provided a vast amount of information on the function and mechanism of TR. Although the enzyme reduces disulfide containing substrates, it has a broad substrate spectrum and also targets other nondisulfide substrates such hydrogen peroxide and selenite. The general mechanism of the enzyme is initiated upon transfer of electrons from NADPH via a bound FAD to the N-terminal redox active site. A second thiol-disulfide exchange step occurs resulting in the reduction of the C-terminal disulfide by the N-terminal redox center. Once reduced, the attacking nucleophile initiates attack on the disulfide of thioredoxin.