transsulfuration pathway

transsulfuration pathway,

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Homocysteine concentrations are also regulated by the activity of the transsulfuration pathway, which is the only route to degrade homocysteine and thus irreversibly consume the methionine backbone. In this pathway, the homocysteine sulfur atom is transferred to serine to make cysteine. Transsulfuration occurs exclusively in the liver, brain, and pancreas; in the brain it is required to support glutathione synthesis (Vitvitsky et al., 2006). Cystathionine beta synthetase (CBS) is the first enzyme in this pathway and has an SAM regulatory site that activates the enzyme. Mutation of the site results in homocystinuria (Kluijtmans et al., 1996). Through the synthesis of reduced cysteine, this pathway contributes to glutathione synthesis and thus cellular redox homeostasis. By generating a reduced cysteine, it conserves an NADPH equivalent that would otherwise be required to reduce extracellular cystine taken in from the circulation (Eriksson et al., 2015).

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Placeholder 湯偉晉編寫的英文字典

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Placeholder 湯偉晉編寫的英文字典

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