This is an outstanding review of sulfur amino acids by Tesseraud et al . Sulfur amino acids have a very significant place amongst amino acids due to their numerous roles Protein synthesis is affected when an insufficient level of sulfur amino acids is available. This defect may originate from dietary amino acid deficiency and/or excessive amino acid utilisation for other purposes such as the synthesis of glutathione and acute-phase proteins during catabolic stress. Sulfur amino acids are recognised to exert other significant functions since they are precursors of essential molecules, They are precursors of major components such as glutatione, taurine, H2S and sulfates and act on oxidative status and signalling pathways. Methionine has a central role in epigenetic regulation with its effect on DNA methylatio. Many questions still remain unanswered due to the complexity of the mechanisms involved. Moreover, surprising effects of dietary sulfur amino acids have been reported, with the development of disorders in cases of both deficiency and excess. These findings indicate the importance of defining adequate levels of intake and providing a rationale for nutritional advice.
Tesseraud et al 2009 Role of sulfur amino acids in controlling nutrient metabolism and cell functions: implications for nutrition British Journal of Nutrition,, vol 101, pp 1132-1139